diff options
Diffstat (limited to 'sos-code-article6/sos')
| -rw-r--r-- | sos-code-article6/sos/assert.c | 44 | ||||
| -rw-r--r-- | sos-code-article6/sos/assert.h | 45 | ||||
| -rw-r--r-- | sos-code-article6/sos/errno.h | 40 | ||||
| -rw-r--r-- | sos-code-article6/sos/klibc.c | 308 | ||||
| -rw-r--r-- | sos-code-article6/sos/klibc.h | 103 | ||||
| -rw-r--r-- | sos-code-article6/sos/kmalloc.c | 113 | ||||
| -rw-r--r-- | sos-code-article6/sos/kmalloc.h | 63 | ||||
| -rw-r--r-- | sos-code-article6/sos/kmem_slab.c | 812 | ||||
| -rw-r--r-- | sos-code-article6/sos/kmem_slab.h | 206 | ||||
| -rw-r--r-- | sos-code-article6/sos/kmem_vmm.c | 606 | ||||
| -rw-r--r-- | sos-code-article6/sos/kmem_vmm.h | 113 | ||||
| -rw-r--r-- | sos-code-article6/sos/list.h | 186 | ||||
| -rw-r--r-- | sos-code-article6/sos/macros.h | 41 | ||||
| -rw-r--r-- | sos-code-article6/sos/main.c | 1162 | ||||
| -rw-r--r-- | sos-code-article6/sos/physmem.c | 319 | ||||
| -rw-r--r-- | sos-code-article6/sos/physmem.h | 147 | ||||
| -rw-r--r-- | sos-code-article6/sos/types.h | 52 |
17 files changed, 4360 insertions, 0 deletions
diff --git a/sos-code-article6/sos/assert.c b/sos-code-article6/sos/assert.c new file mode 100644 index 0000000..2bc0d41 --- /dev/null +++ b/sos-code-article6/sos/assert.c @@ -0,0 +1,44 @@ +/* Copyright (C) 2004 The KOS Team + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ + +#include <sos/klibc.h> +#include <drivers/bochs.h> +#include <drivers/x86_videomem.h> + +#include "assert.h" + +void sos_display_fatal_error(const char *format, /* args */...) +{ + char buff[256]; + va_list ap; + + asm("cli\n"); /* disable interrupts -- x86 only */ \ + + va_start(ap, format); + vsnprintf(buff, sizeof(buff), format, ap); + va_end(ap); + + sos_bochs_putstring(buff); sos_bochs_putstring("\n"); + sos_x86_videomem_putstring(23, 0, + SOS_X86_VIDEO_BG_BLACK + | SOS_X86_VIDEO_FG_LTRED , buff); + + /* Infinite loop: processor halted */ + for ( ; ; ) + asm("hlt\n"); +} diff --git a/sos-code-article6/sos/assert.h b/sos-code-article6/sos/assert.h new file mode 100644 index 0000000..9fcfec0 --- /dev/null +++ b/sos-code-article6/sos/assert.h @@ -0,0 +1,45 @@ +/* Copyright (C) 2004 The KOS Team + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#ifndef _SOS_ASSERT_H_ +#define _SOS_ASSERT_H_ + + +void sos_display_fatal_error(const char *format, /* args */...) + __attribute__ ((format (printf, 1, 2), noreturn)); + + +/** + * If the expr is FALSE, print a message and halt the machine + */ +#define SOS_ASSERT_FATAL(expr) \ + ({ \ + int __res=(int)(expr); \ + if (! __res) \ + sos_display_fatal_error("%s@%s:%d Assertion " # expr " failed", \ + __PRETTY_FUNCTION__, __FILE__, __LINE__); \ + }) + + +#define SOS_FATAL_ERROR(fmt,args...) \ + ({ \ + sos_display_fatal_error("%s@%s:%d FATAL: " fmt, \ + __PRETTY_FUNCTION__, __FILE__, __LINE__, \ + ##args); \ + }) + +#endif /* _SOS_ASSERT_H_ */ diff --git a/sos-code-article6/sos/errno.h b/sos-code-article6/sos/errno.h new file mode 100644 index 0000000..bdc2a11 --- /dev/null +++ b/sos-code-article6/sos/errno.h @@ -0,0 +1,40 @@ +/* Copyright (C) 2004 The SOS Team + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#ifndef _SOS_ERRNO_H_ +#define _SOS_ERRNO_H_ + +/** + * @file errno.h + * + * SOS return value codes and errors. + */ + +/* Positive values of the error codes */ +#define SOS_OK 0 /* No error */ +#define SOS_EINVAL 1 /* Invalid argument */ +#define SOS_ENOSUP 2 /* Operation not supported */ +#define SOS_ENOMEM 3 /* No available memory */ +#define SOS_EBUSY 4 /* Object or device still in use */ +#define SOS_EFATAL 255 /* Internal fatal error */ + +/* A negative value means that an error occured. For + * example -SOS_EINVAL means that the error was "invalid + * argument" */ +typedef int sos_ret_t; + +#endif /* _SOS_ERRNO_H_ */ diff --git a/sos-code-article6/sos/klibc.c b/sos-code-article6/sos/klibc.c new file mode 100644 index 0000000..4442842 --- /dev/null +++ b/sos-code-article6/sos/klibc.c @@ -0,0 +1,308 @@ +/* Copyright (C) 2004 David Decotigny (with INSA Rennes for vsnprintf) + Copyright (C) 2003 The KOS Team + Copyright (C) 1999 Free Software Foundation + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#include "klibc.h" + +/* For an optimized version, see BSD sources ;) */ +void *memcpy(void *dst0, const void *src0, register unsigned int size) +{ + char *dst; + const char *src; + for (dst = (char*)dst0, src = (const char*)src0 ; + size > 0 ; + dst++, src++, size--) + *dst = *src; + return dst0; +} + +/* ditto */ +void *memset(void *dst0, register int c, register unsigned int length) +{ + char *dst; + for (dst = (char*) dst0 ; + length > 0 ; + dst++, length --) + *dst = (char)c; + return dst0; +} + +int memcmp(const void *s1, const void *s2, sos_size_t len) +{ + const unsigned char *c1, *c2; + unsigned int i; + + for (i = 0, c1 = s1, c2 = s2; i < len; i++, c1++, c2++) + { + if(*c1 != *c2) + return *c1 - *c2; + } + + return 0; +} + + +unsigned int strlen(register const char *str) +{ + unsigned int retval = 0; + + while (*str++) + retval++; + + return retval; +} + + +unsigned int strnlen(const char * s, sos_size_t count) +{ + const char *sc; + + for (sc = s; count-- && *sc != '\0'; ++sc) + /* nothing */continue; + + return sc - s; +} + + +char *strzcpy(register char *dst, register const char *src, register int len) +{ + int i; + + if (len <= 0) + return dst; + + for (i = 0; i < len; i++) + { + dst[i] = src[i]; + if(src[i] == '\0') + return dst; + } + + dst[len-1] = '\0'; + return dst; +} + + +char *strzcat (char *dest, const char *src, sos_size_t n) +{ + char *res = dest; + + for ( ; *dest ; dest++); + + for ( ; *src ; src++, dest++) { + *dest = *src; + n--; + if (n <= 0) + break; + } + + *dest = '\0'; + return res; +} + +int strcmp(register const char *s1, register const char *s2) +{ + while (*s1 == *s2++) + if (*s1++ == 0) + return (0); + + return (*(const unsigned char *)s1 - *(const unsigned char *)(s2 - 1)); +} + + +int strncmp(register const char *s1, register const char *s2, register int len) +{ + char c1 = '\0', c2 = '\0'; + + while (len > 0) + { + c1 = (unsigned char) *s1++; + c2 = (unsigned char) *s2++; + if (c1 == '\0' || c1 != c2) + return c1 - c2; + len--; + } + + return c1 - c2; +} + + +static unsigned long int _random_seed = 93186752; + +/** + * The following code is borrowed from Glenn Rhoads. + * http://remus.rutgers.edu/~rhoads/Code/code.html + * License to be defined... + */ +unsigned long int random (void) +{ +/* The following parameters are recommended settings based on research + uncomment the one you want. */ + +/* For RAND_MAX == 4294967291 */ + static unsigned int a = 1588635695, q = 2, r = 1117695901; +/* static unsigned int a = 1223106847, m = 4294967291U, q = 3, r = 625646750;*/ +/* static unsigned int a = 279470273, m = 4294967291U, q = 15, r = 102913196;*/ + +/* For RAND_MAX == 2147483647 */ +/* static unsigned int a = 1583458089, m = 2147483647, q = 1, r = 564025558; */ +/* static unsigned int a = 784588716, m = 2147483647, q = 2, r = 578306215; */ +/* static unsigned int a = 16807, m = 2147483647, q = 127773, r = 2836; */ +/* static unsigned int a = 950706376, m = 2147483647, q = 2, r = 246070895; */ + + _random_seed = a*(_random_seed % q) - r*(_random_seed / q); + return _random_seed; +} + + +void srandom (unsigned long int seed) +{ + _random_seed = seed; +} + + +/* I (d2) borrowed and rewrote this for Nachos/INSA Rennes. Thanks to + them for having kindly allowed me to do so. */ +int vsnprintf(char *buff, sos_size_t len, const char * format, va_list ap) +{ + sos_size_t i, result; + + if (!buff || !format || (len < 0)) + return -1; + +#define PUTCHAR(thechar) \ + do { \ + if (result < len-1) \ + *buff++ = (thechar); \ + result++; \ + } while (0) + + result = 0; + for(i=0 ; format[i] != '\0' ; i++){ + switch (format[i]) + { + case '%': + i++; + switch(format[i]) + { + case '%': + { + PUTCHAR('%'); + break; + } + case 'i':; + case 'd': + { + int integer = va_arg(ap,int); + int cpt2 = 0; + char buff_int[16]; + + if (integer<0) + PUTCHAR('-'); + /* Ne fait pas integer = -integer ici parce que INT_MIN + n'a pas d'equivalent positif (int = [-2^31, 2^31-1]) */ + + do { + int m10 = integer%10; + m10 = (m10 < 0)? -m10:m10; + buff_int[cpt2++]=(char)('0'+ m10); + integer=integer/10; + } while(integer!=0); + + for(cpt2 = cpt2 - 1 ; cpt2 >= 0 ; cpt2--) + PUTCHAR(buff_int[cpt2]); + + break; + } + + case 'c': + { + int value = va_arg(ap,int); + PUTCHAR((char)value); + break; + } + + case 's': + { + char *string = va_arg(ap,char *); + if (! string) + string = "(null)"; + for( ; *string != '\0' ; string++) + PUTCHAR(*string); + break; + } + + case 'p': + PUTCHAR('0'); + PUTCHAR('x'); + case 'x': + { + unsigned int hexa = va_arg(ap,int); + unsigned int nb; + int i, had_nonzero = 0; + for(i=0 ; i < 8 ; i++) + { + nb = (unsigned int)(hexa << (i*4)); + nb = (nb >> 28) & 0xf; + // Skip the leading zeros + if (nb == 0) + { + if (had_nonzero) + PUTCHAR('0'); + } + else + { + had_nonzero = 1; + if (nb < 10) + PUTCHAR('0'+nb); + else + PUTCHAR('a'+(nb-10)); + } + } + if (! had_nonzero) + PUTCHAR('0'); + break; + } + break; + + default: + PUTCHAR('%'); + PUTCHAR(format[i]); + } + break; + + default: + PUTCHAR(format[i]); + } + } + + *buff = '\0'; + return result; +} + + +int snprintf(char * buff, sos_size_t len, const char *format, ...) +{ + va_list ap; + + va_start(ap, format); + len = vsnprintf(buff, len, format, ap); + va_end(ap); + + return len; +} diff --git a/sos-code-article6/sos/klibc.h b/sos-code-article6/sos/klibc.h new file mode 100644 index 0000000..7002778 --- /dev/null +++ b/sos-code-article6/sos/klibc.h @@ -0,0 +1,103 @@ +/* Copyright (C) 2003 The KOS Team + Copyright (C) 1999 Free Software Foundation + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#ifndef _SOS_KLIBC_H_ +#define _SOS_KLIBC_H_ + +/** + * @file klibc.h + * + * Basic libc-style support for common useful functions (string.h, + * stdarg.h), some with slight non-standard behavior (see comments). + * + * Most of the prototypes of these functions are borrowed from + * FreeBSD, but their implementation (in klibc.c) come either from Kos + * (GPL v2) or from David Decotigny (SOS). + */ + +#include <sos/types.h> + +/* string.h functions */ + +void *memcpy(void *dst, const void *src, register unsigned int size ) ; +void *memset(void *dst, register int c, register unsigned int length ) ; +int memcmp(const void *s1, const void *s2, sos_size_t n); + +unsigned int strlen( register const char *str) ; +unsigned int strnlen(const char * s, sos_size_t maxlen); + +/** + * @note Same as strncpy(), with a slightly different semantic. + * Actually, strncpy(3C) says " The result will not be null-terminated + * if the length of 'from' is n or more.". Here, 'dst' is ALWAYS + * null-terminated. And its total len will ALWAYS be <= len, with + * null-terminating-char included. + */ +char *strzcpy( register char *dst, register const char *src, + register int len ) ; + +/** + * @note Same as strncat(), with the same semantic : 'dst' is ALWAYS + * null-terminated. And its total len will ALWAYS be <= len, with + * null-terminating-char included. + */ +char *strzcat (char *dest, const char *src, + const sos_size_t len); + +int strcmp(register const char *s1, register const char *s2 ); +int strncmp(register const char *s1, register const char *s2, + register int len ); + +/* Basic stdarg.h macros. Taken from gcc support files */ +#define __GNUC_VA_LIST +typedef void *__gnuc_va_list; +typedef __gnuc_va_list va_list; +#define __va_rounded_size(TYPE) \ + (((sizeof (TYPE) + sizeof (int) - 1) / sizeof (int)) * sizeof (int)) +#define va_start(AP, LASTARG) \ + (AP = ((__gnuc_va_list) __builtin_next_arg (LASTARG))) +#define va_end(AP) \ + ((void)0) +#define va_arg(AP, TYPE) \ + (AP = (__gnuc_va_list) ((char *) (AP) + __va_rounded_size (TYPE)), \ + *((TYPE *) (void *) ((char *) (AP) - __va_rounded_size (TYPE)))) +#define __va_copy(dest, src) \ + (dest) = (src) + +/* stdarg.h functions. There might be a non-standard behavior: there + will always be a trailing '\0' in the resulting string */ +int vsnprintf(char *, sos_size_t, const char *, va_list); +int snprintf(char *, sos_size_t, const char *, /*args*/ ...) + __attribute__ ((format (printf, 3, 4))); + + +/* + * Pseudo-random generation functions. Useful to do some coverage + * tests. + */ + +/* Amplitude of the random number generation */ +#define RAND_MAX 4294967291U + +/* Pseudo-random number generation (MT unsafe) */ +unsigned long int random (void); + +/* Set random seed (MT unsafe) */ +void srandom (unsigned long int seed); + +#endif /* _SOS_KLIBC_H_ */ diff --git a/sos-code-article6/sos/kmalloc.c b/sos-code-article6/sos/kmalloc.c new file mode 100644 index 0000000..62d948d --- /dev/null +++ b/sos-code-article6/sos/kmalloc.c @@ -0,0 +1,113 @@ +/* Copyright (C) 2004 David Decotigny + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ + +#include <sos/assert.h> +#include <sos/macros.h> + +#include "physmem.h" +#include "kmem_vmm.h" +#include "kmem_slab.h" + +#include "kmalloc.h" + +/* The cache structures for these caches, the object size, their + names, and some number of pages that contain them. They might not + necessarily be powers of 2s. */ +static struct { + const char *name; + sos_size_t object_size; + sos_count_t pages_per_slab; + struct sos_kslab_cache *cache; +} kmalloc_cache[] = + { + { "kmalloc 8B objects", 8, 1 }, + { "kmalloc 16B objects", 16, 1 }, + { "kmalloc 32B objects", 32, 1 }, + { "kmalloc 64B objects", 64, 1 }, + { "kmalloc 128B objects", 128, 1 }, + { "kmalloc 256B objects", 256, 2 }, + { "kmalloc 1024B objects", 1024, 2 }, + { "kmalloc 2048B objects", 2048, 3 }, + { "kmalloc 4096B objects", 4096, 4 }, + { "kmalloc 8192B objects", 8192, 8 }, + { "kmalloc 16384B objects", 16384, 12 }, + { NULL, 0, 0, NULL } + }; + + +sos_ret_t sos_kmalloc_subsystem_setup() +{ + int i; + for (i = 0 ; kmalloc_cache[i].object_size != 0 ; i ++) + { + struct sos_kslab_cache *new_cache; + new_cache = sos_kmem_cache_create(kmalloc_cache[i].name, + kmalloc_cache[i].object_size, + kmalloc_cache[i].pages_per_slab, + 0, + SOS_KSLAB_CREATE_MAP + ); + SOS_ASSERT_FATAL(new_cache != NULL); + kmalloc_cache[i].cache = new_cache; + } + return SOS_OK; +} + + +sos_vaddr_t sos_kmalloc(sos_size_t size, sos_ui32_t flags) +{ + /* Look for a suitable pre-allocated kmalloc cache */ + int i; + for (i = 0 ; kmalloc_cache[i].object_size != 0 ; i ++) + { + if (kmalloc_cache[i].object_size >= size) + return sos_kmem_cache_alloc(kmalloc_cache[i].cache, + (flags + & SOS_KMALLOC_ATOMIC)? + SOS_KSLAB_ALLOC_ATOMIC:0); + } + + /* none found yet => we directly use the kmem_vmm subsystem to + allocate whole pages */ + return sos_kmem_vmm_alloc(SOS_PAGE_ALIGN_SUP(size) / SOS_PAGE_SIZE, + ( (flags + & SOS_KMALLOC_ATOMIC)? + SOS_KMEM_VMM_ATOMIC:0) + | SOS_KMEM_VMM_MAP + ); +} + + +sos_ret_t sos_kfree(sos_vaddr_t vaddr) +{ + /* The trouble here is that we aren't sure whether this object is a + slab object in a pre-allocated kmalloc cache, or an object + directly allocated as a kmem_vmm region. */ + + /* We first pretend this object is allocated in a pre-allocated + kmalloc cache */ + if (! sos_kmem_cache_free(vaddr)) + return SOS_OK; /* Great ! We guessed right ! */ + + /* Here we're wrong: it appears not to be an object in a + pre-allocated kmalloc cache. So we try to pretend this is a + kmem_vmm area */ + return sos_kmem_vmm_free(vaddr); +} + + diff --git a/sos-code-article6/sos/kmalloc.h b/sos-code-article6/sos/kmalloc.h new file mode 100644 index 0000000..3f35b9d --- /dev/null +++ b/sos-code-article6/sos/kmalloc.h @@ -0,0 +1,63 @@ +/* Copyright (C) 2004 David Decotigny + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#ifndef _SOS_KMALLOC_H_ +#define _SOS_KMALLOC_H_ + +/** + * @file kmalloc.h + * + * Simple malloc-style wrapper to kmem_vmm.h and kmem_slab.h for + * "anonymous" objects (ie not associated to any precise slab cache). + */ + +#include <sos/types.h> +#include <sos/errno.h> + + +/** + * Iniatilize the kmalloc subsystem, ie pre-allocate a series of caches. + */ +sos_ret_t sos_kmalloc_subsystem_setup(void); + +/* + * sos_kmalloc flags + */ +/** sos_kmalloc() should succeed without blocking, or return NULL */ +#define SOS_KMALLOC_ATOMIC 1 + +/** + * Allocate a kernel object of the given size in the most suited slab + * cache if size can be handled by one of the pre-allocated caches, or + * using directly the range allocator otherwise. The object will + * allways be mapped in physical memory (ie implies + * SOS_KSLAB_CREATE_MAP and SOS_KMEM_VMM_MAP). + * + * @param size The size of the object + * @param flags The allocation flags (SOS_KMALLOC_* flags) + */ +sos_vaddr_t sos_kmalloc(sos_size_t size, sos_ui32_t flags); + +/** + * @note you are perfectly allowed to give the address of the + * kernel image, or the address of the bios area here, it will work: + * the kernel/bios WILL be "deallocated". But if you really want to do + * this, well..., do expect some "surprises" ;) + */ +sos_ret_t sos_kfree(sos_vaddr_t vaddr); + +#endif /* _SOS_KMALLOC_H_ */ diff --git a/sos-code-article6/sos/kmem_slab.c b/sos-code-article6/sos/kmem_slab.c new file mode 100644 index 0000000..49a1527 --- /dev/null +++ b/sos-code-article6/sos/kmem_slab.c @@ -0,0 +1,812 @@ +/* Copyright (C) 2000 Thomas Petazzoni + Copyright (C) 2004 David Decotigny + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#include <sos/macros.h> +#include <sos/klibc.h> +#include <sos/list.h> +#include <sos/assert.h> +#include <hwcore/paging.h> +#include <sos/physmem.h> +#include <sos/kmem_vmm.h> + +#include "kmem_slab.h" + +/* Dimensioning constants */ +#define NB_PAGES_IN_SLAB_OF_CACHES 1 +#define NB_PAGES_IN_SLAB_OF_RANGES 1 + +/** The structure of a slab cache */ +struct sos_kslab_cache +{ + char *name; + + /* non mutable characteristics of this slab */ + sos_size_t original_obj_size; /* asked object size */ + sos_size_t alloc_obj_size; /* actual object size, taking the + alignment constraints into account */ + sos_count_t nb_objects_per_slab; + sos_count_t nb_pages_per_slab; + sos_count_t min_free_objects; + +/* slab cache flags */ +// #define SOS_KSLAB_CREATE_MAP (1<<0) /* See kmem_slab.h */ +// #define SOS_KSLAB_CREATE_ZERO (1<<1) /* " " " " " " " " */ +#define ON_SLAB (1<<31) /* struct sos_kslab is included inside the slab */ + sos_ui32_t flags; + + /* Supervision data (updated at run-time) */ + sos_count_t nb_free_objects; + + /* The lists of slabs owned by this cache */ + struct sos_kslab *slab_list; /* head = non full, tail = full */ + + /* The caches are linked together on the kslab_cache_list */ + struct sos_kslab_cache *prev, *next; +}; + + +/** The structure of a slab */ +struct sos_kslab +{ + /** Number of free objects on this slab */ + sos_count_t nb_free; + + /** The list of these free objects */ + struct sos_kslab_free_object *free; + + /** The address of the associated range structure */ + struct sos_kmem_range *range; + + /** Virtual start address of this range */ + sos_vaddr_t first_object; + + /** Slab cache owning this slab */ + struct sos_kslab_cache *cache; + + /** Links to the other slabs managed by the same cache */ + struct sos_kslab *prev, *next; +}; + + +/** The structure of the free objects in the slab */ +struct sos_kslab_free_object +{ + struct sos_kslab_free_object *prev, *next; +}; + +/** The cache of slab caches */ +static struct sos_kslab_cache *cache_of_struct_kslab_cache; + +/** The cache of slab structures for non-ON_SLAB caches */ +static struct sos_kslab_cache *cache_of_struct_kslab; + +/** The list of slab caches */ +static struct sos_kslab_cache *kslab_cache_list; + +/* Helper function to initialize a cache structure */ +static sos_ret_t +cache_initialize(/*out*/struct sos_kslab_cache *the_cache, + const char* name, + sos_size_t obj_size, + sos_count_t pages_per_slab, + sos_count_t min_free_objs, + sos_ui32_t cache_flags) +{ + unsigned int space_left; + sos_size_t alloc_obj_size; + + if (obj_size <= 0) + return -SOS_EINVAL; + + /* Default allocation size is the requested one */ + alloc_obj_size = obj_size; + + /* Make sure the requested size is large enough to store a + free_object structure */ + if (alloc_obj_size < sizeof(struct sos_kslab_free_object)) + alloc_obj_size = sizeof(struct sos_kslab_free_object); + + /* Align obj_size on 4 bytes */ + alloc_obj_size = SOS_ALIGN_SUP(alloc_obj_size, sizeof(int)); + + /* Make sure supplied number of pages per slab is consistent with + actual allocated object size */ + if (alloc_obj_size > pages_per_slab*SOS_PAGE_SIZE) + return -SOS_EINVAL; + + /* Refuse too large slabs */ + if (pages_per_slab > MAX_PAGES_PER_SLAB) + return -SOS_ENOMEM; + + /* Fills in the cache structure */ + memset(the_cache, 0x0, sizeof(struct sos_kslab_cache)); + the_cache->name = (char*)name; + the_cache->flags = cache_flags; + the_cache->original_obj_size = obj_size; + the_cache->alloc_obj_size = alloc_obj_size; + the_cache->min_free_objects = min_free_objs; + the_cache->nb_pages_per_slab = pages_per_slab; + + /* Small size objets => the slab structure is allocated directly in + the slab */ + if(alloc_obj_size <= sizeof(struct sos_kslab)) + the_cache->flags |= ON_SLAB; + + /* + * Compute the space left once the maximum number of objects + * have been allocated in the slab + */ + space_left = the_cache->nb_pages_per_slab*SOS_PAGE_SIZE; + if(the_cache->flags & ON_SLAB) + space_left -= sizeof(struct sos_kslab); + the_cache->nb_objects_per_slab = space_left / alloc_obj_size; + space_left -= the_cache->nb_objects_per_slab*alloc_obj_size; + + /* Make sure a single slab is large enough to contain the minimum + number of objects requested */ + if (the_cache->nb_objects_per_slab < min_free_objs) + return -SOS_EINVAL; + + /* If there is now enough place for both the objects and the slab + structure, then make the slab structure ON_SLAB */ + if (space_left >= sizeof(struct sos_kslab)) + the_cache->flags |= ON_SLAB; + + return SOS_OK; +} + + +/** Helper function to add a new slab for the given cache. */ +static sos_ret_t +cache_add_slab(struct sos_kslab_cache *kslab_cache, + sos_vaddr_t vaddr_slab, + struct sos_kslab *slab) +{ + int i; + + /* Setup the slab structure */ + memset(slab, 0x0, sizeof(struct sos_kslab)); + slab->cache = kslab_cache; + + /* Establish the address of the first free object */ + slab->first_object = vaddr_slab; + + /* Account for this new slab in the cache */ + slab->nb_free = kslab_cache->nb_objects_per_slab; + kslab_cache->nb_free_objects += slab->nb_free; + + /* Build the list of free objects */ + for (i = 0 ; i < kslab_cache->nb_objects_per_slab ; i++) + { + sos_vaddr_t obj_vaddr; + + /* Set object's address */ + obj_vaddr = slab->first_object + i*kslab_cache->alloc_obj_size; + + /* Add it to the list of free objects */ + list_add_tail(slab->free, + (struct sos_kslab_free_object *)obj_vaddr); + } + + /* Add the slab to the cache's slab list: add the head of the list + since this slab is non full */ + list_add_head(kslab_cache->slab_list, slab); + + return SOS_OK; +} + + +/** Helper function to allocate a new slab for the given kslab_cache */ +static sos_ret_t +cache_grow(struct sos_kslab_cache *kslab_cache, + sos_ui32_t alloc_flags) +{ + sos_ui32_t range_alloc_flags; + + struct sos_kmem_range *new_range; + sos_vaddr_t new_range_start; + + struct sos_kslab *new_slab; + + /* + * Setup the flags for the range allocation + */ + range_alloc_flags = 0; + + /* Atomic ? */ + if (alloc_flags & SOS_KSLAB_ALLOC_ATOMIC) + range_alloc_flags |= SOS_KMEM_VMM_ATOMIC; + + /* Need physical mapping NOW ? */ + if (kslab_cache->flags & (SOS_KSLAB_CREATE_MAP + | SOS_KSLAB_CREATE_ZERO)) + range_alloc_flags |= SOS_KMEM_VMM_MAP; + + /* Allocate the range */ + new_range = sos_kmem_vmm_new_range(kslab_cache->nb_pages_per_slab, + range_alloc_flags, + & new_range_start); + if (! new_range) + return -SOS_ENOMEM; + + /* Allocate the slab structure */ + if (kslab_cache->flags & ON_SLAB) + { + /* Slab structure is ON the slab: simply set its address to the + end of the range */ + sos_vaddr_t slab_vaddr + = new_range_start + kslab_cache->nb_pages_per_slab*SOS_PAGE_SIZE + - sizeof(struct sos_kslab); + new_slab = (struct sos_kslab*)slab_vaddr; + } + else + { + /* Slab structure is OFF the slab: allocate it from the cache of + slab structures */ + sos_vaddr_t slab_vaddr + = sos_kmem_cache_alloc(cache_of_struct_kslab, + alloc_flags); + if (! slab_vaddr) + { + sos_kmem_vmm_del_range(new_range); + return -SOS_ENOMEM; + } + new_slab = (struct sos_kslab*)slab_vaddr; + } + + cache_add_slab(kslab_cache, new_range_start, new_slab); + new_slab->range = new_range; + + /* Set the backlink from range to this slab */ + sos_kmem_vmm_set_slab(new_range, new_slab); + + return SOS_OK; +} + + +/** + * Helper function to release a slab + * + * The corresponding range is always deleted, except when the @param + * must_del_range_now is not set. This happens only when the function + * gets called from sos_kmem_cache_release_struct_range(), to avoid + * large recursions. + */ +static sos_ret_t +cache_release_slab(struct sos_kslab *slab, + sos_bool_t must_del_range_now) +{ + struct sos_kslab_cache *kslab_cache = slab->cache; + struct sos_kmem_range *range = slab->range; + + SOS_ASSERT_FATAL(kslab_cache != NULL); + SOS_ASSERT_FATAL(range != NULL); + SOS_ASSERT_FATAL(slab->nb_free == slab->cache->nb_objects_per_slab); + + /* First, remove the slab from the slabs' list of the cache */ + list_delete(kslab_cache->slab_list, slab); + slab->cache->nb_free_objects -= slab->nb_free; + + /* Release the slab structure if it is OFF slab */ + if (! (slab->cache->flags & ON_SLAB)) + sos_kmem_cache_free((sos_vaddr_t)slab); + + /* Ok, the range is not bound to any slab anymore */ + sos_kmem_vmm_set_slab(range, NULL); + + /* Always delete the range now, unless we are told not to do so (see + sos_kmem_cache_release_struct_range() below) */ + if (must_del_range_now) + return sos_kmem_vmm_del_range(range); + + return SOS_OK; +} + + +/** + * Helper function to create the initial cache of caches, with a very + * first slab in it, so that new cache structures can be simply allocated. + * @return the cache structure for the cache of caches + */ +static struct sos_kslab_cache * +create_cache_of_caches(sos_vaddr_t vaddr_first_slab_of_caches, + int nb_pages) +{ + /* The preliminary cache structure we need in order to allocate the + first slab in the cache of caches (allocated on the stack !) */ + struct sos_kslab_cache fake_cache_of_caches; + + /* The real cache structure for the cache of caches */ + struct sos_kslab_cache *real_cache_of_caches; + + /* The kslab structure for this very first slab */ + struct sos_kslab *slab_of_caches; + + /* Init the cache structure for the cache of caches */ + if (cache_initialize(& fake_cache_of_caches, + "Caches", sizeof(struct sos_kslab_cache), + nb_pages, 0, SOS_KSLAB_CREATE_MAP | ON_SLAB)) + /* Something wrong with the parameters */ + return NULL; + + memset((void*)vaddr_first_slab_of_caches, 0x0, nb_pages*SOS_PAGE_SIZE); + + /* Add the pages for the 1st slab of caches */ + slab_of_caches = (struct sos_kslab*)(vaddr_first_slab_of_caches + + nb_pages*SOS_PAGE_SIZE + - sizeof(struct sos_kslab)); + + /* Add the abovementioned 1st slab to the cache of caches */ + cache_add_slab(& fake_cache_of_caches, + vaddr_first_slab_of_caches, + slab_of_caches); + + /* Now we allocate a cache structure, which will be the real cache + of caches, ie a cache structure allocated INSIDE the cache of + caches, not inside the stack */ + real_cache_of_caches + = (struct sos_kslab_cache*) sos_kmem_cache_alloc(& fake_cache_of_caches, + 0); + /* We initialize it */ + memcpy(real_cache_of_caches, & fake_cache_of_caches, + sizeof(struct sos_kslab_cache)); + /* We need to update the slab's 'cache' field */ + slab_of_caches->cache = real_cache_of_caches; + + /* Add the cache to the list of slab caches */ + list_add_tail(kslab_cache_list, real_cache_of_caches); + + return real_cache_of_caches; +} + + +/** + * Helper function to create the initial cache of ranges, with a very + * first slab in it, so that new kmem_range structures can be simply + * allocated. + * @return the cache of kmem_range + */ +static struct sos_kslab_cache * +create_cache_of_ranges(sos_vaddr_t vaddr_first_slab_of_ranges, + sos_size_t sizeof_struct_range, + int nb_pages) +{ + /* The cache structure for the cache of kmem_range */ + struct sos_kslab_cache *cache_of_ranges; + + /* The kslab structure for the very first slab of ranges */ + struct sos_kslab *slab_of_ranges; + + cache_of_ranges = (struct sos_kslab_cache*) + sos_kmem_cache_alloc(cache_of_struct_kslab_cache, + 0); + if (! cache_of_ranges) + return NULL; + + /* Init the cache structure for the cache of ranges with min objects + per slab = 2 !!! */ + if (cache_initialize(cache_of_ranges, + "struct kmem_range", + sizeof_struct_range, + nb_pages, 2, SOS_KSLAB_CREATE_MAP | ON_SLAB)) + /* Something wrong with the parameters */ + return NULL; + + /* Add the cache to the list of slab caches */ + list_add_tail(kslab_cache_list, cache_of_ranges); + + /* + * Add the first slab for this cache + */ + memset((void*)vaddr_first_slab_of_ranges, 0x0, nb_pages*SOS_PAGE_SIZE); + + /* Add the pages for the 1st slab of ranges */ + slab_of_ranges = (struct sos_kslab*)(vaddr_first_slab_of_ranges + + nb_pages*SOS_PAGE_SIZE + - sizeof(struct sos_kslab)); + + cache_add_slab(cache_of_ranges, + vaddr_first_slab_of_ranges, + slab_of_ranges); + + return cache_of_ranges; +} + + +struct sos_kslab_cache * +sos_kmem_cache_subsystem_setup_prepare(sos_vaddr_t kernel_core_base, + sos_vaddr_t kernel_core_top, + sos_size_t sizeof_struct_range, + /* results */ + struct sos_kslab **first_struct_slab_of_caches, + sos_vaddr_t *first_slab_of_caches_base, + sos_count_t *first_slab_of_caches_nb_pages, + struct sos_kslab **first_struct_slab_of_ranges, + sos_vaddr_t *first_slab_of_ranges_base, + sos_count_t *first_slab_of_ranges_nb_pages) +{ + int i; + sos_ret_t retval; + sos_vaddr_t vaddr; + + /* The cache of ranges we are about to allocate */ + struct sos_kslab_cache *cache_of_ranges; + + /* In the begining, there isn't any cache */ + kslab_cache_list = NULL; + cache_of_struct_kslab = NULL; + cache_of_struct_kslab_cache = NULL; + + /* + * Create the cache of caches, initialised with 1 allocated slab + */ + + /* Allocate the pages needed for the 1st slab of caches, and map them + in kernel space, right after the kernel */ + *first_slab_of_caches_base = SOS_PAGE_ALIGN_SUP(kernel_core_top); + for (i = 0, vaddr = *first_slab_of_caches_base ; + i < NB_PAGES_IN_SLAB_OF_CACHES ; + i++, vaddr += SOS_PAGE_SIZE) + { + sos_paddr_t ppage_paddr; + + ppage_paddr + = sos_physmem_ref_physpage_new(FALSE); + SOS_ASSERT_FATAL(ppage_paddr != (sos_paddr_t)NULL); + + retval = sos_paging_map(ppage_paddr, vaddr, + FALSE, + SOS_VM_MAP_ATOMIC + | SOS_VM_MAP_PROT_READ + | SOS_VM_MAP_PROT_WRITE); + SOS_ASSERT_FATAL(retval == SOS_OK); + + retval = sos_physmem_unref_physpage(ppage_paddr); + SOS_ASSERT_FATAL(retval == FALSE); + } + + /* Create the cache of caches */ + *first_slab_of_caches_nb_pages = NB_PAGES_IN_SLAB_OF_CACHES; + cache_of_struct_kslab_cache + = create_cache_of_caches(*first_slab_of_caches_base, + NB_PAGES_IN_SLAB_OF_CACHES); + SOS_ASSERT_FATAL(cache_of_struct_kslab_cache != NULL); + + /* Retrieve the slab that should have been allocated */ + *first_struct_slab_of_caches + = list_get_head(cache_of_struct_kslab_cache->slab_list); + + + /* + * Create the cache of ranges, initialised with 1 allocated slab + */ + *first_slab_of_ranges_base = vaddr; + /* Allocate the 1st slab */ + for (i = 0, vaddr = *first_slab_of_ranges_base ; + i < NB_PAGES_IN_SLAB_OF_RANGES ; + i++, vaddr += SOS_PAGE_SIZE) + { + sos_paddr_t ppage_paddr; + + ppage_paddr + = sos_physmem_ref_physpage_new(FALSE); + SOS_ASSERT_FATAL(ppage_paddr != (sos_paddr_t)NULL); + + retval = sos_paging_map(ppage_paddr, vaddr, + FALSE, + SOS_VM_MAP_ATOMIC + | SOS_VM_MAP_PROT_READ + | SOS_VM_MAP_PROT_WRITE); + SOS_ASSERT_FATAL(retval == SOS_OK); + + retval = sos_physmem_unref_physpage(ppage_paddr); + SOS_ASSERT_FATAL(retval == FALSE); + } + + /* Create the cache of ranges */ + *first_slab_of_ranges_nb_pages = NB_PAGES_IN_SLAB_OF_RANGES; + cache_of_ranges = create_cache_of_ranges(*first_slab_of_ranges_base, + sizeof_struct_range, + NB_PAGES_IN_SLAB_OF_RANGES); + SOS_ASSERT_FATAL(cache_of_ranges != NULL); + + /* Retrieve the slab that should have been allocated */ + *first_struct_slab_of_ranges + = list_get_head(cache_of_ranges->slab_list); + + /* + * Create the cache of slabs, without any allocated slab yet + */ + cache_of_struct_kslab + = sos_kmem_cache_create("off-slab slab structures", + sizeof(struct sos_kslab), + 1, + 0, + SOS_KSLAB_CREATE_MAP); + SOS_ASSERT_FATAL(cache_of_struct_kslab != NULL); + + return cache_of_ranges; +} + + +sos_ret_t +sos_kmem_cache_subsystem_setup_commit(struct sos_kslab *first_struct_slab_of_caches, + struct sos_kmem_range *first_range_of_caches, + struct sos_kslab *first_struct_slab_of_ranges, + struct sos_kmem_range *first_range_of_ranges) +{ + first_struct_slab_of_caches->range = first_range_of_caches; + first_struct_slab_of_ranges->range = first_range_of_ranges; + return SOS_OK; +} + + +struct sos_kslab_cache * +sos_kmem_cache_create(const char* name, + sos_size_t obj_size, + sos_count_t pages_per_slab, + sos_count_t min_free_objs, + sos_ui32_t cache_flags) +{ + struct sos_kslab_cache *new_cache; + + /* Allocate the new cache */ + new_cache = (struct sos_kslab_cache*) + sos_kmem_cache_alloc(cache_of_struct_kslab_cache, + 0/* NOT ATOMIC */); + if (! new_cache) + return NULL; + + if (cache_initialize(new_cache, name, obj_size, + pages_per_slab, min_free_objs, + cache_flags)) + { + /* Something was wrong */ + sos_kmem_cache_free((sos_vaddr_t)new_cache); + return NULL; + } + + /* Add the cache to the list of slab caches */ + list_add_tail(kslab_cache_list, new_cache); + + /* if the min_free_objs is set, pre-allocate a slab */ + if (min_free_objs) + { + if (cache_grow(new_cache, 0 /* Not atomic */) != SOS_OK) + { + sos_kmem_cache_destroy(new_cache); + return NULL; /* Not enough memory */ + } + } + + return new_cache; +} + + +sos_ret_t sos_kmem_cache_destroy(struct sos_kslab_cache *kslab_cache) +{ + int nb_slabs; + struct sos_kslab *slab; + + if (! kslab_cache) + return -SOS_EINVAL; + + /* Refuse to destroy the cache if there are any objects still + allocated */ + list_foreach(kslab_cache->slab_list, slab, nb_slabs) + { + if (slab->nb_free != kslab_cache->nb_objects_per_slab) + return -SOS_EBUSY; + } + + /* Remove all the slabs */ + while ((slab = list_get_head(kslab_cache->slab_list)) != NULL) + { + cache_release_slab(slab, TRUE); + } + + /* Remove the cache */ + return sos_kmem_cache_free((sos_vaddr_t)kslab_cache); +} + + +sos_vaddr_t sos_kmem_cache_alloc(struct sos_kslab_cache *kslab_cache, + sos_ui32_t alloc_flags) +{ + sos_vaddr_t obj_vaddr; + struct sos_kslab * slab_head; +#define ALLOC_RET return + + /* If the slab at the head of the slabs' list has no free object, + then the other slabs don't either => need to allocate a new + slab */ + if ((! kslab_cache->slab_list) + || (! list_get_head(kslab_cache->slab_list)->free)) + { + if (cache_grow(kslab_cache, alloc_flags) != SOS_OK) + /* Not enough memory or blocking alloc */ + ALLOC_RET( (sos_vaddr_t)NULL); + } + + /* Here: we are sure that list_get_head(kslab_cache->slab_list) + exists *AND* that list_get_head(kslab_cache->slab_list)->free is + NOT NULL */ + slab_head = list_get_head(kslab_cache->slab_list); + SOS_ASSERT_FATAL(slab_head != NULL); + + /* Allocate the object at the head of the slab at the head of the + slabs' list */ + obj_vaddr = (sos_vaddr_t)list_pop_head(slab_head->free); + slab_head->nb_free --; + kslab_cache->nb_free_objects --; + + /* If needed, reset object's contents */ + if (kslab_cache->flags & SOS_KSLAB_CREATE_ZERO) + memset((void*)obj_vaddr, 0x0, kslab_cache->alloc_obj_size); + + /* Slab is now full ? */ + if (slab_head->free == NULL) + { + /* Transfer it at the tail of the slabs' list */ + struct sos_kslab *slab; + slab = list_pop_head(kslab_cache->slab_list); + list_add_tail(kslab_cache->slab_list, slab); + } + + /* + * For caches that require a minimum amount of free objects left, + * allocate a slab if needed. + * + * Notice the "== min_objects - 1": we did not write " < + * min_objects" because for the cache of kmem structure, this would + * lead to an chicken-and-egg problem, since cache_grow below would + * call cache_alloc again for the kmem_vmm cache, so we return here + * with the same cache. If the test were " < min_objects", then we + * would call cache_grow again for the kmem_vmm cache again and + * again... until we reach the bottom of our stack (infinite + * recursion). By telling precisely "==", then the cache_grow would + * only be called the first time. + */ + if ((kslab_cache->min_free_objects > 0) + && (kslab_cache->nb_free_objects == (kslab_cache->min_free_objects - 1))) + { + /* No: allocate a new slab now */ + if (cache_grow(kslab_cache, alloc_flags) != SOS_OK) + { + /* Not enough free memory or blocking alloc => undo the + allocation */ + sos_kmem_cache_free(obj_vaddr); + ALLOC_RET( (sos_vaddr_t)NULL); + } + } + + ALLOC_RET(obj_vaddr); +} + + +/** + * Helper function to free the object located at the given address. + * + * @param empty_slab is the address of the slab to release, if removing + * the object causes the slab to become empty. + */ +inline static +sos_ret_t +free_object(sos_vaddr_t vaddr, + struct sos_kslab ** empty_slab) +{ + struct sos_kslab_cache *kslab_cache; + + /* Lookup the slab containing the object in the slabs' list */ + struct sos_kslab *slab = sos_kmem_vmm_resolve_slab(vaddr); + + /* By default, consider that the slab will not become empty */ + *empty_slab = NULL; + + /* Did not find the slab */ + if (! slab) + return -SOS_EINVAL; + + SOS_ASSERT_FATAL(slab->cache); + kslab_cache = slab->cache; + + /* + * Check whether the address really could mark the start of an actual + * allocated object + */ + /* Address multiple of an object's size ? */ + if (( (vaddr - slab->first_object) + % kslab_cache->alloc_obj_size) != 0) + return -SOS_EINVAL; + /* Address not too large ? */ + if (( (vaddr - slab->first_object) + / kslab_cache->alloc_obj_size) >= kslab_cache->nb_objects_per_slab) + return -SOS_EINVAL; + + /* + * Ok: we now release the object + */ + + /* Did find a full slab => will not be full any more => move it + to the head of the slabs' list */ + if (! slab->free) + { + list_delete(kslab_cache->slab_list, slab); + list_add_head(kslab_cache->slab_list, slab); + } + + /* Release the object */ + list_add_head(slab->free, (struct sos_kslab_free_object*)vaddr); + slab->nb_free++; + kslab_cache->nb_free_objects++; + SOS_ASSERT_FATAL(slab->nb_free <= slab->cache->nb_objects_per_slab); + + /* Cause the slab to be released if it becomes empty, and if we are + allowed to do it */ + if ((slab->nb_free >= kslab_cache->nb_objects_per_slab) + && (kslab_cache->nb_free_objects - slab->nb_free + >= kslab_cache->min_free_objects)) + { + *empty_slab = slab; + } + + return SOS_OK; +} + + +sos_ret_t sos_kmem_cache_free(sos_vaddr_t vaddr) +{ + sos_ret_t retval; + struct sos_kslab *empty_slab; + + /* Remove the object from the slab */ + retval = free_object(vaddr, & empty_slab); + if (retval != SOS_OK) + return retval; + + /* Remove the slab and the underlying range if needed */ + if (empty_slab != NULL) + return cache_release_slab(empty_slab, TRUE); + + return SOS_OK; +} + + +struct sos_kmem_range * +sos_kmem_cache_release_struct_range(struct sos_kmem_range *the_range) +{ + sos_ret_t retval; + struct sos_kslab *empty_slab; + + /* Remove the object from the slab */ + retval = free_object((sos_vaddr_t)the_range, & empty_slab); + if (retval != SOS_OK) + return NULL; + + /* Remove the slab BUT NOT the underlying range if needed */ + if (empty_slab != NULL) + { + struct sos_kmem_range *empty_range = empty_slab->range; + SOS_ASSERT_FATAL(cache_release_slab(empty_slab, FALSE) == SOS_OK); + SOS_ASSERT_FATAL(empty_range != NULL); + return empty_range; + } + + return NULL; +} + diff --git a/sos-code-article6/sos/kmem_slab.h b/sos-code-article6/sos/kmem_slab.h new file mode 100644 index 0000000..1f28ff9 --- /dev/null +++ b/sos-code-article6/sos/kmem_slab.h @@ -0,0 +1,206 @@ +/* Copyright (C) 2000 Thomas Petazzoni + Copyright (C) 2004 David Decotigny + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#ifndef _SOS_KMEM_SLAB_H_ +#define _SOS_KMEM_SLAB_H_ + +/** + * @file kmem_slab.h + * + * Kernel Memory Allocator based on Bonwick's slab llocator (Solaris + * 2.4, Linux 2.4). This allocator achieves good memory utilization + * ratio (memory effectively used / memory requested) ie limited + * fragmentation, while elegantly handling cache-effect considerations + * (TLB locality through the notion of "cache" of slabs, and the + * dcache utilization through the notion of cache colouring to + * decrease the conflicts in the dcache for accesses to different data + * in the same cache). + * + * This allocator relies on the range allocator (kmem_vmm.h) to + * allocate the slabs, which itself relies on the slab allocator to + * allocate its "range" data structures, thus leading to a + * chicken-and-egg problem. We solve this problem by introducing the + * notion of "min_free_objs" for the slab caches, in order for the cache + * of ranges to always have enough ranges in reserve to complete the + * range allocation before being urged to allocate a new slab of + * ranges, which would require the allocation of a new range. + * + * Compared to Bonwick's recommendations, we don't handle ctor/dtor + * routines on the objects, so that we can alter the objects once they + * are set free. Thus, the list of free object is stored in the free + * objects themselves, not alongside the objects (this also implies that + * the SOS_KSLAB_CREATE_MAP flag below is meaningless). We also don't + * implement the cache colouring (trivial to add, but we omit it for + * readability reasons), and the only alignment constraint we respect + * is that allocated objects are aligned on a 4B boundary: for other + * alignment constraints, the user must integrate them in the + * "object_size" parameter to "sos_kmem_cache_create()". + * + * References : + * - J. Bonwick's paper, "The slab allocator: An object-caching kernel + * memory allocator", In USENIX Summer 1994 Technical Conference + * - The bible, aka "Unix internals : the new frontiers" (section + * 12.10), Uresh Vahalia, Prentice Hall 1996, ISBN 0131019082 + * - "The Linux slab allocator", B. Fitzgibbons, + * http://www.cc.gatech.edu/people/home/bradf/cs7001/proj2/ + * - The Kos, http://kos.enix.org/ + */ +#include <sos/types.h> +#include <sos/errno.h> + +/** Opaque data structure that defines a Cache of slabs */ +struct sos_kslab_cache; + +/** Opaque data structure that defines a slab. Exported only to + kmem_vmm.h */ +struct sos_kslab; + +#include "kmem_vmm.h" + + +/** The maximum allowed pages for each slab */ +#define MAX_PAGES_PER_SLAB 32 /* 128 kB */ + + +/** + * Initialize the slab cache of slab caches, and prepare the cache of + * kmem_range for kmem_vmm. + * + * @param kernel_core_base The virtual address of the first byte used + * by the kernel code/data + * + * @param kernel_core_top The virtual address of the first byte after + * the kernel code/data. + * + * @param sizeof_struct_range the size of the objects (aka "struct + * sos_kmem_vmm_ranges") to be allocated in the cache of ranges + * + * @param first_struct_slab_of_caches (output value) the virtual + * address of the first slab structure that gets allocated for the + * cache of caches. The function actually manually allocate the first + * slab of the cache of caches because of a chicken-and-egg thing. The + * address of the slab is used by the kmem_vmm_setup routine to + * finalize the allocation of the slab, in order for it to behave like + * a real slab afterwards. + * + * @param first_slab_of_caches_base (output value) the virtual address + * of the slab associated to the slab structure. + * + * @param first_slab_of_caches_nb_pages (output value) the number of + * (virtual) pages used by the first slab of the cache of caches. + * + * @param first_struct_slab_of_ranges (output value) the virtual address + * of the first slab that gets allocated for the cache of ranges. Same + * explanation as above. + * + * @param first_slab_of_ranges_base (output value) the virtual address + * of the slab associated to the slab structure. + * + * @param first_slab_of_ranges_nb_pages (output value) the number of + * (virtual) pages used by the first slab of the cache of ranges. + * + * @return the cache of kmem_range immediatly usable + */ +struct sos_kslab_cache * +sos_kmem_cache_subsystem_setup_prepare(sos_vaddr_t kernel_core_base, + sos_vaddr_t kernel_core_top, + sos_size_t sizeof_struct_range, + /* results */ + struct sos_kslab **first_struct_slab_of_caches, + sos_vaddr_t *first_slab_of_caches_base, + sos_count_t *first_slab_of_caches_nb_pages, + struct sos_kslab **first_struct_slab_of_ranges, + sos_vaddr_t *first_slab_of_ranges_base, + sos_count_t *first_slab_of_ranges_nb_pages); + +/** + * Update the configuration of the cache subsystem once the vmm + * subsystem has been fully initialized + */ +sos_ret_t +sos_kmem_cache_subsystem_setup_commit(struct sos_kslab *first_struct_slab_of_caches, + struct sos_kmem_range *first_range_of_caches, + struct sos_kslab *first_struct_slab_of_ranges, + struct sos_kmem_range *first_range_of_ranges); + + +/* + * Flags for sos_kmem_cache_create() + */ +/** The slabs should be initially mapped in physical memory */ +#define SOS_KSLAB_CREATE_MAP (1<<0) +/** The object should always be set to zero at allocation (implies + SOS_KSLAB_CREATE_MAP) */ +#define SOS_KSLAB_CREATE_ZERO (1<<1) + +/** + * @note this function MAY block (involved allocations are not atomic) + * @param name must remain valid during the whole cache's life + * (shallow copy) ! + * @param cache_flags An or-ed combination of the SOS_KSLAB_CREATE_* flags + */ +struct sos_kslab_cache * +sos_kmem_cache_create(const char* name, + sos_size_t object_size, + sos_count_t pages_per_slab, + sos_count_t min_free_objects, + sos_ui32_t cache_flags); + +sos_ret_t sos_kmem_cache_destroy(struct sos_kslab_cache *kslab_cache); + + +/* + * Flags for sos_kmem_cache_alloc() + */ +/** Allocation should either succeed or fail, without blocking */ +#define SOS_KSLAB_ALLOC_ATOMIC (1<<0) + +/** + * Allocate an object from the given cache. + * + * @param alloc_flags An or-ed combination of the SOS_KSLAB_ALLOC_* flags + */ +sos_vaddr_t sos_kmem_cache_alloc(struct sos_kslab_cache *kslab_cache, + sos_ui32_t alloc_flags); + + +/** + * Free an object (assumed to be already allocated and not already + * free) at the given virtual address. + */ +sos_ret_t sos_kmem_cache_free(sos_vaddr_t vaddr); + + +/* + * Function reserved to kmem_vmm.c. Does almost everything + * sos_kmem_cache_free() does, except it does not call + * sos_kmem_vmm_del_range() if it needs to. This is aimed at avoiding + * large recursion when a range is freed with + * sos_kmem_vmm_del_range(). + * + * @param the_range The range structure to free + * + * @return NULL when the range containing 'the_range' still contains + * other ranges, or the address of the range which owned 'the_range' + * if it becomes empty. + */ +struct sos_kmem_range * +sos_kmem_cache_release_struct_range(struct sos_kmem_range *the_range); + + +#endif /* _SOS_KMEM_SLAB_H_ */ diff --git a/sos-code-article6/sos/kmem_vmm.c b/sos-code-article6/sos/kmem_vmm.c new file mode 100644 index 0000000..ea2fdf1 --- /dev/null +++ b/sos-code-article6/sos/kmem_vmm.c @@ -0,0 +1,606 @@ +/* Copyright (C) 2000 Thomas Petazzoni + Copyright (C) 2004 David Decotigny + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ + +#include <sos/list.h> +#include <sos/physmem.h> +#include <hwcore/paging.h> +#include <sos/assert.h> + +#include "kmem_vmm.h" + +/** The structure of a range of kernel-space virtual addresses */ +struct sos_kmem_range +{ + sos_vaddr_t base_vaddr; + sos_count_t nb_pages; + + /* The slab owning this range, or NULL */ + struct sos_kslab *slab; + + struct sos_kmem_range *prev, *next; +}; +const int sizeof_struct_sos_kmem_range = sizeof(struct sos_kmem_range); + +/** The ranges are SORTED in (strictly) ascending base addresses */ +static struct sos_kmem_range *kmem_free_range_list, *kmem_used_range_list; + +/** The slab cache for the kmem ranges */ +static struct sos_kslab_cache *kmem_range_cache; + + + +/** Helper function to get the closest preceding or containing + range for the given virtual address */ +static struct sos_kmem_range * +get_closest_preceding_kmem_range(struct sos_kmem_range *the_list, + sos_vaddr_t vaddr) +{ + int nb_elements; + struct sos_kmem_range *a_range, *ret_range; + + /* kmem_range list is kept SORTED, so we exit as soon as vaddr >= a + range base address */ + ret_range = NULL; + list_foreach(the_list, a_range, nb_elements) + { + if (vaddr < a_range->base_vaddr) + return ret_range; + ret_range = a_range; + } + + /* This will always be the LAST range in the kmem area */ + return ret_range; +} + + +/** + * Helper function to lookup a free range large enough to hold nb_pages + * pages (first fit) + */ +static struct sos_kmem_range *find_suitable_free_range(sos_count_t nb_pages) +{ + int nb_elements; + struct sos_kmem_range *r; + + list_foreach(kmem_free_range_list, r, nb_elements) + { + if (r->nb_pages >= nb_pages) + return r; + } + + return NULL; +} + + +/** + * Helper function to add a_range in the_list, in strictly ascending order. + * + * @return The (possibly) new head of the_list + */ +static struct sos_kmem_range *insert_range(struct sos_kmem_range *the_list, + struct sos_kmem_range *a_range) +{ + struct sos_kmem_range *prec_used; + + /** Look for any preceding range */ + prec_used = get_closest_preceding_kmem_range(the_list, + a_range->base_vaddr); + /** insert a_range /after/ this prec_used */ + if (prec_used != NULL) + list_insert_after(the_list, prec_used, a_range); + else /* Insert at the beginning of the list */ + list_add_head(the_list, a_range); + + return the_list; +} + + +/** + * Helper function to retrieve the range owning the given vaddr, by + * scanning the physical memory first if vaddr is mapped in RAM + */ +static struct sos_kmem_range *lookup_range(sos_vaddr_t vaddr) +{ + struct sos_kmem_range *range; + + /* First: try to retrieve the physical page mapped at this address */ + sos_paddr_t ppage_paddr = SOS_PAGE_ALIGN_INF(sos_paging_get_paddr(vaddr)); + + if (ppage_paddr) + { + range = sos_physmem_get_kmem_range(ppage_paddr); + + /* If a page is mapped at this address, it is EXPECTED that it + is really associated with a range */ + SOS_ASSERT_FATAL(range != NULL); + } + + /* Otherwise scan the list of used ranges, looking for the range + owning the address */ + else + { + range = get_closest_preceding_kmem_range(kmem_used_range_list, + vaddr); + /* Not found */ + if (! range) + return NULL; + + /* vaddr not covered by this range */ + if ( (vaddr < range->base_vaddr) + || (vaddr >= (range->base_vaddr + range->nb_pages*SOS_PAGE_SIZE)) ) + return NULL; + } + + return range; +} + + +/** + * Helper function for sos_kmem_vmm_setup() to initialize a new range + * that maps a given area as free or as already used. + * This function either succeeds or halts the whole system. + */ +static struct sos_kmem_range * +create_range(sos_bool_t is_free, + sos_vaddr_t base_vaddr, + sos_vaddr_t top_vaddr, + struct sos_kslab *associated_slab) +{ + struct sos_kmem_range *range; + + SOS_ASSERT_FATAL(SOS_IS_PAGE_ALIGNED(base_vaddr)); + SOS_ASSERT_FATAL(SOS_IS_PAGE_ALIGNED(top_vaddr)); + + if ((top_vaddr - base_vaddr) < SOS_PAGE_SIZE) + return NULL; + + range = (struct sos_kmem_range*)sos_kmem_cache_alloc(kmem_range_cache, + SOS_KSLAB_ALLOC_ATOMIC); + SOS_ASSERT_FATAL(range != NULL); + + range->base_vaddr = base_vaddr; + range->nb_pages = (top_vaddr - base_vaddr) / SOS_PAGE_SIZE; + + if (is_free) + { + list_add_tail(kmem_free_range_list, + range); + } + else + { + sos_vaddr_t vaddr; + range->slab = associated_slab; + list_add_tail(kmem_used_range_list, + range); + + /* Ok, set the range owner for the pages in this page */ + for (vaddr = base_vaddr ; + vaddr < top_vaddr ; + vaddr += SOS_PAGE_SIZE) + { + sos_paddr_t ppage_paddr = sos_paging_get_paddr(vaddr); + SOS_ASSERT_FATAL((void*)ppage_paddr != NULL); + sos_physmem_set_kmem_range(ppage_paddr, range); + } + } + + return range; +} + + +sos_ret_t +sos_kmem_vmm_subsystem_setup(sos_vaddr_t kernel_core_base, + sos_vaddr_t kernel_core_top, + sos_vaddr_t bootstrap_stack_bottom_vaddr, + sos_vaddr_t bootstrap_stack_top_vaddr) +{ + struct sos_kslab *first_struct_slab_of_caches, + *first_struct_slab_of_ranges; + sos_vaddr_t first_slab_of_caches_base, + first_slab_of_caches_nb_pages, + first_slab_of_ranges_base, + first_slab_of_ranges_nb_pages; + struct sos_kmem_range *first_range_of_caches, + *first_range_of_ranges; + + list_init(kmem_free_range_list); + list_init(kmem_used_range_list); + + kmem_range_cache + = sos_kmem_cache_subsystem_setup_prepare(kernel_core_base, + kernel_core_top, + sizeof(struct sos_kmem_range), + & first_struct_slab_of_caches, + & first_slab_of_caches_base, + & first_slab_of_caches_nb_pages, + & first_struct_slab_of_ranges, + & first_slab_of_ranges_base, + & first_slab_of_ranges_nb_pages); + SOS_ASSERT_FATAL(kmem_range_cache != NULL); + + /* Mark virtual addresses 16kB - Video as FREE */ + create_range(TRUE, + SOS_KMEM_VMM_BASE, + SOS_PAGE_ALIGN_INF(BIOS_N_VIDEO_START), + NULL); + + /* Mark virtual addresses in Video hardware mapping as NOT FREE */ + create_range(FALSE, + SOS_PAGE_ALIGN_INF(BIOS_N_VIDEO_START), + SOS_PAGE_ALIGN_SUP(BIOS_N_VIDEO_END), + NULL); + + /* Mark virtual addresses Video - Kernel as FREE */ + create_range(TRUE, + SOS_PAGE_ALIGN_SUP(BIOS_N_VIDEO_END), + SOS_PAGE_ALIGN_INF(kernel_core_base), + NULL); + + /* Mark virtual addresses in Kernel code/data up to the bootstrap stack + as NOT FREE */ + create_range(FALSE, + SOS_PAGE_ALIGN_INF(kernel_core_base), + bootstrap_stack_bottom_vaddr, + NULL); + + /* Mark virtual addresses in the bootstrap stack as NOT FREE too, + but in another vmm region in order to be un-allocated later */ + create_range(FALSE, + bootstrap_stack_bottom_vaddr, + bootstrap_stack_top_vaddr, + NULL); + + /* Mark the remaining virtual addresses in Kernel code/data after + the bootstrap stack as NOT FREE */ + create_range(FALSE, + bootstrap_stack_top_vaddr, + SOS_PAGE_ALIGN_SUP(kernel_core_top), + NULL); + + /* Mark virtual addresses in the first slab of the cache of caches + as NOT FREE */ + SOS_ASSERT_FATAL(SOS_PAGE_ALIGN_SUP(kernel_core_top) + == first_slab_of_caches_base); + SOS_ASSERT_FATAL(first_struct_slab_of_caches != NULL); + first_range_of_caches + = create_range(FALSE, + first_slab_of_caches_base, + first_slab_of_caches_base + + first_slab_of_caches_nb_pages*SOS_PAGE_SIZE, + first_struct_slab_of_caches); + + /* Mark virtual addresses in the first slab of the cache of ranges + as NOT FREE */ + SOS_ASSERT_FATAL((first_slab_of_caches_base + + first_slab_of_caches_nb_pages*SOS_PAGE_SIZE) + == first_slab_of_ranges_base); + SOS_ASSERT_FATAL(first_struct_slab_of_ranges != NULL); + first_range_of_ranges + = create_range(FALSE, + first_slab_of_ranges_base, + first_slab_of_ranges_base + + first_slab_of_ranges_nb_pages*SOS_PAGE_SIZE, + first_struct_slab_of_ranges); + + /* Mark virtual addresses after these slabs as FREE */ + create_range(TRUE, + first_slab_of_ranges_base + + first_slab_of_ranges_nb_pages*SOS_PAGE_SIZE, + SOS_KMEM_VMM_TOP, + NULL); + + /* Update the cache subsystem so that the artificially-created + caches of caches and ranges really behave like *normal* caches (ie + those allocated by the normal slab API) */ + sos_kmem_cache_subsystem_setup_commit(first_struct_slab_of_caches, + first_range_of_caches, + first_struct_slab_of_ranges, + first_range_of_ranges); + + return SOS_OK; +} + + +/** + * Allocate a new kernel area spanning one or multiple pages. + * + * @eturn a new range structure + */ +struct sos_kmem_range *sos_kmem_vmm_new_range(sos_count_t nb_pages, + sos_ui32_t flags, + sos_vaddr_t * range_start) +{ + struct sos_kmem_range *free_range, *new_range; + + if (nb_pages <= 0) + return NULL; + + /* Find a suitable free range to hold the size-sized object */ + free_range = find_suitable_free_range(nb_pages); + if (free_range == NULL) + return NULL; + + /* If range has exactly the requested size, just move it to the + "used" list */ + if(free_range->nb_pages == nb_pages) + { + list_delete(kmem_free_range_list, free_range); + kmem_used_range_list = insert_range(kmem_used_range_list, + free_range); + /* The new_range is exactly the free_range */ + new_range = free_range; + } + + /* Otherwise the range is bigger than the requested size, split it. + This involves reducing its size, and allocate a new range, which + is going to be added to the "used" list */ + else + { + /* free_range split in { new_range | free_range } */ + new_range = (struct sos_kmem_range*) + sos_kmem_cache_alloc(kmem_range_cache, + (flags & SOS_KMEM_VMM_ATOMIC)? + SOS_KSLAB_ALLOC_ATOMIC:0); + if (! new_range) + return NULL; + + new_range->base_vaddr = free_range->base_vaddr; + new_range->nb_pages = nb_pages; + free_range->base_vaddr += nb_pages*SOS_PAGE_SIZE; + free_range->nb_pages -= nb_pages; + + /* free_range is still at the same place in the list */ + /* insert new_range in the used list */ + kmem_used_range_list = insert_range(kmem_used_range_list, + new_range); + } + + /* By default, the range is not associated with any slab */ + new_range->slab = NULL; + + /* If mapping of physical pages is needed, map them now */ + if (flags & SOS_KMEM_VMM_MAP) + { + int i; + for (i = 0 ; i < nb_pages ; i ++) + { + /* Get a new physical page */ + sos_paddr_t ppage_paddr + = sos_physmem_ref_physpage_new(! (flags & SOS_KMEM_VMM_ATOMIC)); + + /* Map the page in kernel space */ + if (ppage_paddr) + { + if (sos_paging_map(ppage_paddr, + new_range->base_vaddr + + i * SOS_PAGE_SIZE, + FALSE /* Not a user page */, + ((flags & SOS_KMEM_VMM_ATOMIC)? + SOS_VM_MAP_ATOMIC:0) + | SOS_VM_MAP_PROT_READ + | SOS_VM_MAP_PROT_WRITE)) + { + /* Failed => force unallocation, see below */ + sos_physmem_unref_physpage(ppage_paddr); + ppage_paddr = (sos_paddr_t)NULL; + } + else + { + /* Success : page can be unreferenced since it is + now mapped */ + sos_physmem_unref_physpage(ppage_paddr); + } + } + + /* Undo the allocation if failed to allocate or map a new page */ + if (! ppage_paddr) + { + sos_kmem_vmm_del_range(new_range); + return NULL; + } + + /* Ok, set the range owner for this page */ + sos_physmem_set_kmem_range(ppage_paddr, new_range); + } + } + /* ... Otherwise: Demand Paging will do the job */ + + if (range_start) + *range_start = new_range->base_vaddr; + + return new_range; +} + + +sos_ret_t sos_kmem_vmm_del_range(struct sos_kmem_range *range) +{ + int i; + struct sos_kmem_range *ranges_to_free; + list_init(ranges_to_free); + + SOS_ASSERT_FATAL(range != NULL); + SOS_ASSERT_FATAL(range->slab == NULL); + + /* Remove the range from the 'USED' list now */ + list_delete(kmem_used_range_list, range); + + /* + * The following do..while() loop is here to avoid an indirect + * recursion: if we call directly kmem_cache_free() from inside the + * current function, we take the risk to re-enter the current function + * (sos_kmem_vmm_del_range()) again, which may cause problem if it + * in turn calls kmem_slab again and sos_kmem_vmm_del_range again, + * and again and again. This may happen while freeing ranges of + * struct sos_kslab... + * + * To avoid this,we choose to call a special function of kmem_slab + * doing almost the same as sos_kmem_cache_free(), but which does + * NOT call us (ie sos_kmem_vmm_del_range()): instead WE add the + * range that is to be freed to a list, and the do..while() loop is + * here to process this list ! The recursion is replaced by + * classical iterations. + */ + do + { + /* Ok, we got the range. Now, insert this range in the free list */ + kmem_free_range_list = insert_range(kmem_free_range_list, range); + + /* Unmap the physical pages */ + for (i = 0 ; i < range->nb_pages ; i ++) + { + /* This will work even if no page is mapped at this address */ + sos_paging_unmap(range->base_vaddr + i*SOS_PAGE_SIZE); + } + + /* Eventually coalesce it with prev/next free ranges (there is + always a valid prev/next link since the list is circular). Note: + the tests below will lead to correct behaviour even if the list + is limited to the 'range' singleton, at least as long as the + range is not zero-sized */ + /* Merge with preceding one ? */ + if (range->prev->base_vaddr + range->prev->nb_pages*SOS_PAGE_SIZE + == range->base_vaddr) + { + struct sos_kmem_range *empty_range_of_ranges = NULL; + struct sos_kmem_range *prec_free = range->prev; + + /* Merge them */ + prec_free->nb_pages += range->nb_pages; + list_delete(kmem_free_range_list, range); + + /* Mark the range as free. This may cause the slab owning + the range to become empty */ + empty_range_of_ranges = + sos_kmem_cache_release_struct_range(range); + + /* If this causes the slab owning the range to become empty, + add the range corresponding to the slab at the end of the + list of the ranges to be freed: it will be actually freed + in one of the next iterations of the do{} loop. */ + if (empty_range_of_ranges != NULL) + { + list_delete(kmem_used_range_list, empty_range_of_ranges); + list_add_tail(ranges_to_free, empty_range_of_ranges); + } + + /* Set range to the beginning of this coelescion */ + range = prec_free; + } + + /* Merge with next one ? [NO 'else' since range may be the result of + the merge above] */ + if (range->base_vaddr + range->nb_pages*SOS_PAGE_SIZE + == range->next->base_vaddr) + { + struct sos_kmem_range *empty_range_of_ranges = NULL; + struct sos_kmem_range *next_range = range->next; + + /* Merge them */ + range->nb_pages += next_range->nb_pages; + list_delete(kmem_free_range_list, next_range); + + /* Mark the next_range as free. This may cause the slab + owning the next_range to become empty */ + empty_range_of_ranges = + sos_kmem_cache_release_struct_range(next_range); + + /* If this causes the slab owning the next_range to become + empty, add the range corresponding to the slab at the end + of the list of the ranges to be freed: it will be + actually freed in one of the next iterations of the + do{} loop. */ + if (empty_range_of_ranges != NULL) + { + list_delete(kmem_used_range_list, empty_range_of_ranges); + list_add_tail(ranges_to_free, empty_range_of_ranges); + } + } + + + /* If deleting the range(s) caused one or more range(s) to be + freed, get the next one to free */ + if (list_is_empty(ranges_to_free)) + range = NULL; /* No range left to free */ + else + range = list_pop_head(ranges_to_free); + + } + /* Stop when there is no range left to be freed for now */ + while (range != NULL); + + return SOS_OK; +} + + +sos_vaddr_t sos_kmem_vmm_alloc(sos_count_t nb_pages, + sos_ui32_t flags) +{ + struct sos_kmem_range *range + = sos_kmem_vmm_new_range(nb_pages, + flags, + NULL); + if (! range) + return (sos_vaddr_t)NULL; + + return range->base_vaddr; +} + + +sos_ret_t sos_kmem_vmm_free(sos_vaddr_t vaddr) +{ + struct sos_kmem_range *range = lookup_range(vaddr); + + /* We expect that the given address is the base address of the + range */ + if (!range || (range->base_vaddr != vaddr)) + return -SOS_EINVAL; + + /* We expect that this range is not held by any cache */ + if (range->slab != NULL) + return -SOS_EBUSY; + + return sos_kmem_vmm_del_range(range); +} + + +sos_ret_t sos_kmem_vmm_set_slab(struct sos_kmem_range *range, + struct sos_kslab *slab) +{ + if (! range) + return -SOS_EINVAL; + + range->slab = slab; + return SOS_OK; +} + +struct sos_kslab * sos_kmem_vmm_resolve_slab(sos_vaddr_t vaddr) +{ + struct sos_kmem_range *range = lookup_range(vaddr); + if (! range) + return NULL; + + return range->slab; +} + + +sos_bool_t sos_kmem_vmm_is_valid_vaddr(sos_vaddr_t vaddr) +{ + struct sos_kmem_range *range = lookup_range(vaddr); + return (range != NULL); +} diff --git a/sos-code-article6/sos/kmem_vmm.h b/sos-code-article6/sos/kmem_vmm.h new file mode 100644 index 0000000..49b262d --- /dev/null +++ b/sos-code-article6/sos/kmem_vmm.h @@ -0,0 +1,113 @@ +/* Copyright (C) 2000 Thomas Petazzoni + Copyright (C) 2004 David Decotigny + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#ifndef _SOS_KMEM_VMM_H_ +#define _SOS_KMEM_VMM_H_ + +/** + * @file kmem_vmm.h + * + * Kernel Memory Allocator for multiple-page-sized objects residing in + * the kernel (virtual memory) space. Relies on the slab cache + * allocator to allocate its (internal) "range" data structure. + */ + +#include <hwcore/paging.h> + +/* The base and top virtual addresses covered by the kernel allocator */ +#define SOS_KMEM_VMM_BASE 0x4000 /* 16kB */ +#define SOS_KMEM_VMM_TOP SOS_PAGING_MIRROR_VADDR /* 1GB - 4MB */ + +/** Opaque structure used internally and declared here for physmem.h */ +struct sos_kmem_range; + +#include <sos/kmem_slab.h> + +/** + * Mark the areas belonging to SOS_KMEM_VMM_BASE and SOS_KMEM_VMM_TOP + * are either used or free. Those that are already mapped are marked + * as "used", and the 0..SOS_KMEM_VMM_BASE virtual addresses as marked + * as "used" too (to detect incorrect pointer dereferences). + */ +sos_ret_t +sos_kmem_vmm_subsystem_setup(sos_vaddr_t kernel_core_base_vaddr, + sos_vaddr_t kernel_core_top_vaddr, + sos_vaddr_t bootstrap_stack_bottom_vaddr, + sos_vaddr_t bootstrap_stack_top_vaddr); + + +/* + * Flags for kmem_vmm_new_range and kmem_vmm_alloc + */ +/** Physical pages should be immediately mapped */ +#define SOS_KMEM_VMM_MAP (1<<0) +/** Allocation should either success or fail, without blocking */ +#define SOS_KMEM_VMM_ATOMIC (1<<1) + +/** + * Allocate a new kernel area spanning one or multiple pages. + * + * @param range_base_vaddr If not NULL, the start address of the range + * is stored in this location + * @eturn a new range structure + */ +struct sos_kmem_range *sos_kmem_vmm_new_range(sos_size_t nb_pages, + sos_ui32_t flags, + sos_vaddr_t *range_base_vaddr); +sos_ret_t sos_kmem_vmm_del_range(struct sos_kmem_range *range); + + +/** + * Straighforward variant of sos_kmem_vmm_new_range() returning the + * range's start address instead of the range structure + */ +sos_vaddr_t sos_kmem_vmm_alloc(sos_size_t nb_pages, + sos_ui32_t flags); + +/** + * @note you are perfectly allowed to give the address of the + * kernel image, or the address of the bios area here, it will work: + * the kernel/bios WILL be "deallocated". But if you really want to do + * this, well..., do expect some "surprises" ;) + */ +sos_ret_t sos_kmem_vmm_free(sos_vaddr_t vaddr); + + +/** + * @return TRUE when vaddr is covered by any (used) kernel range + */ +sos_bool_t sos_kmem_vmm_is_valid_vaddr(sos_vaddr_t vaddr); + + +/* ***************************** + * Reserved to kmem_slab.c ONLY. + */ +/** + * Associate the range with the given slab. + */ +sos_ret_t sos_kmem_vmm_set_slab(struct sos_kmem_range *range, + struct sos_kslab *slab); + +/** + * Retrieve the (used) slab associated with the range covering vaddr. + * + * @return NULL if the range is not associated with a KMEM range + */ +struct sos_kslab *sos_kmem_vmm_resolve_slab(sos_vaddr_t vaddr); + +#endif /* _SOS_KMEM_VMM_H_ */ diff --git a/sos-code-article6/sos/list.h b/sos-code-article6/sos/list.h new file mode 100644 index 0000000..67e72f3 --- /dev/null +++ b/sos-code-article6/sos/list.h @@ -0,0 +1,186 @@ +/* Copyright (C) 2001 David Decotigny + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#ifndef _SOS_LIST_H_ +#define _SOS_LIST_H_ + +/** + * @file list.h + * + * Circular doubly-linked lists implementation entirely based on C + * macros + */ + + +/* *_named are used when next and prev links are not exactly next + and prev. For instance when we have next_in_team, prev_in_team, + prev_global and next_global */ + +#define list_init_named(list,prev,next) \ + ((list) = NULL) + +#define list_singleton_named(list,item,prev,next) ({ \ + (item)->next = (item)->prev = (item); \ + (list) = (item); \ +}) + +#define list_is_empty_named(list,prev,next) \ + ((list) == NULL) + +#define list_get_head_named(list,prev,next) \ + (list) + +#define list_get_tail_named(list,prev,next) \ + ((list)?((list)->prev):NULL) + +/* Internal macro : insert before the head == insert at tail */ +#define __list_insert_atleft_named(before_this,item,prev,next) ({ \ + (before_this)->prev->next = (item); \ + (item)->prev = (before_this)->prev; \ + (before_this)->prev = (item); \ + (item)->next = (before_this); \ +}) + +/* @note Before_this and item are expected to be valid ! */ +#define list_insert_before_named(list,before_this,item,prev,next) ({ \ + __list_insert_atleft_named(before_this,item,prev,next); \ + if ((list) == (before_this)) (list) = (item); \ +}) + +/** @note After_this and item are expected to be valid ! */ +#define list_insert_after_named(list,after_this,item,prev,next) ({ \ + (after_this)->next->prev = (item); \ + (item)->next = (after_this)->next; \ + (after_this)->next = (item); \ + (item)->prev = (after_this); \ +}) + +#define list_add_head_named(list,item,prev,next) ({ \ + if (list) \ + list_insert_before_named(list,list,item,prev,next); \ + else \ + list_singleton_named(list,item,prev,next); \ + (list) = (item); \ +}) + +#define list_add_tail_named(list,item,prev,next) ({ \ + if (list) \ + __list_insert_atleft_named(list,item,prev,next); \ + else \ + list_singleton_named(list,item,prev,next); \ +}) + +/** @note NO check whether item really is in list ! */ +#define list_delete_named(list,item,prev,next) ({ \ + if ( ((item)->next == (item)) && ((item)->prev == (item)) ) \ + (item)->next = (item)->prev = (list) = NULL; \ + else { \ + (item)->prev->next = (item)->next; \ + (item)->next->prev = (item)->prev; \ + if ((item) == (list)) (list) = (item)->next; \ + (item)->prev = (item)->next = NULL; \ + } \ +}) + +#define list_pop_head_named(list,prev,next) ({ \ + typeof(list) __ret_elt = (list); \ + list_delete_named(list,__ret_elt,prev,next); \ + __ret_elt; }) + +/** Loop statement that iterates through all of its elements, from + head to tail */ +#define list_foreach_forward_named(list,iterator,nb_elements,prev,next) \ + for (nb_elements=0, (iterator) = (list) ; \ + (iterator) && (!nb_elements || ((iterator) != (list))) ; \ + nb_elements++, (iterator) = (iterator)->next ) + +/** Loop statement that iterates through all of its elements, from + tail back to head */ +#define list_foreach_backward_named(list,iterator,nb_elements,prev,next) \ + for (nb_elements=0, (iterator) = list_get_tail_named(list,prev,next) ; \ + (iterator) && (!nb_elements || \ + ((iterator) != list_get_tail_named(list,prev,next))) ; \ + nb_elements++, (iterator) = (iterator)->prev ) + +#define list_foreach_named list_foreach_forward_named + +/** True when we exitted early from the foreach loop (ie break) */ +#define list_foreach_early_break(list,iterator,nb_elements) \ + ((list) && ( \ + ((list) != (iterator)) || \ + ( ((list) == (iterator)) && (nb_elements == 0)) )) + +/** Loop statement that also removes the item at each iteration */ +#define list_collapse_named(list,iterator,prev,next) \ + for ( ; ({ ((iterator) = (list)) ; \ + if (list) list_delete_named(list,iterator,prev,next) ; \ + (iterator); }) ; ) + + +/* + * the same macros : assume that the prev and next fields are really + * named "prev" and "next" + */ + +#define list_init(list) \ + list_init_named(list,prev,next) + +#define list_singleton(list,item) \ + list_singleton_named(list,item,prev,next) + +#define list_is_empty(list) \ + list_is_empty_named(list,prev,next) + +#define list_get_head(list) \ + list_get_head_named(list,prev,next) \ + +#define list_get_tail(list) \ + list_get_tail_named(list,prev,next) \ + +/* @note Before_this and item are expected to be valid ! */ +#define list_insert_after(list,after_this,item) \ + list_insert_after_named(list,after_this,item,prev,next) + +/* @note After_this and item are expected to be valid ! */ +#define list_insert_before(list,before_this,item) \ + list_insert_before_named(list,before_this,item,prev,next) + +#define list_add_head(list,item) \ + list_add_head_named(list,item,prev,next) + +#define list_add_tail(list,item) \ + list_add_tail_named(list,item,prev,next) + +/* @note NO check whether item really is in list ! */ +#define list_delete(list,item) \ + list_delete_named(list,item,prev,next) + +#define list_pop_head(list) \ + list_pop_head_named(list,prev,next) + +#define list_foreach_forward(list,iterator,nb_elements) \ + list_foreach_forward_named(list,iterator,nb_elements,prev,next) + +#define list_foreach_backward(list,iterator,nb_elements) \ + list_foreach_backward_named(list,iterator,nb_elements,prev,next) + +#define list_foreach list_foreach_forward + +#define list_collapse(list,iterator) \ + list_collapse_named(list,iterator,prev,next) + +#endif /* _SOS_LIST_H_ */ diff --git a/sos-code-article6/sos/macros.h b/sos-code-article6/sos/macros.h new file mode 100644 index 0000000..80a05d3 --- /dev/null +++ b/sos-code-article6/sos/macros.h @@ -0,0 +1,41 @@ +/* Copyright (C) 2004 The KOS Team + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#ifndef _SOS_MACROS_H_ +#define _SOS_MACROS_H_ + +/** Align on a boundary (MUST be a power of 2), so that return value <= val */ +#define SOS_ALIGN_INF(val,boundary) \ + (((unsigned)(val)) & (~((boundary)-1))) + +/** Align on a boundary (MUST be a power of 2), so that return value >= val */ +#define SOS_ALIGN_SUP(val,boundary) \ + ({ unsigned int __bnd=(boundary); \ + (((((unsigned)(val))-1) & (~(__bnd - 1))) + __bnd); }) + +/** Check whether val is aligned on a boundary (MUST be a power of 2) */ +#define SOS_IS_ALIGNED(val,boundary) \ + ( 0 == (((unsigned)(val)) & ((boundary)-1)) ) + +/** + * @return TRUE if val is a power of 2. + * @note val is evaluated multiple times + */ +#define SOS_IS_POWER_OF_2(val) \ + ((((val) - 1) & (val)) == 0) + +#endif /* _SOS_MACROS_H_ */ diff --git a/sos-code-article6/sos/main.c b/sos-code-article6/sos/main.c new file mode 100644 index 0000000..37f1d68 --- /dev/null +++ b/sos-code-article6/sos/main.c @@ -0,0 +1,1162 @@ +/* Copyright (C) 2004 The SOS Team + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ + +/* Include definitions of the multiboot standard */ +#include <bootstrap/multiboot.h> +#include <hwcore/idt.h> +#include <hwcore/gdt.h> +#include <hwcore/irq.h> +#include <hwcore/exception.h> +#include <hwcore/i8254.h> +#include <sos/list.h> +#include <sos/physmem.h> +#include <hwcore/paging.h> +#include <sos/kmem_vmm.h> +#include <sos/kmalloc.h> +#include <sos/klibc.h> +#include <sos/assert.h> +#include <drivers/x86_videomem.h> +#include <drivers/bochs.h> + + +/* Helper function to display each bits of a 32bits integer on the + screen as dark or light carrets */ +void display_bits(unsigned char row, unsigned char col, + unsigned char attribute, + sos_ui32_t integer) +{ + int i; + /* Scan each bit of the integer, MSb first */ + for (i = 31 ; i >= 0 ; i--) + { + /* Test if bit i of 'integer' is set */ + int bit_i = (integer & (1 << i)); + /* Ascii 219 => dark carret, Ascii 177 => light carret */ + unsigned char ascii_code = bit_i?219:177; + sos_x86_videomem_putchar(row, col++, + attribute, + ascii_code); + } +} + + +/* Clock IRQ handler */ +static void clk_it(int intid) +{ + static sos_ui32_t clock_count = 0; + + display_bits(0, 48, + SOS_X86_VIDEO_FG_LTGREEN | SOS_X86_VIDEO_BG_BLUE, + clock_count); + clock_count++; +} + + +/* ====================================================================== + * Page fault exception handling + */ + +/* Helper function to dump a backtrace on bochs and/or the console */ + +static void dump_backtrace(const struct sos_cpu_state *cpu_state, + sos_vaddr_t stack_bottom, + sos_size_t stack_size, + sos_bool_t on_console, + sos_bool_t on_bochs) +{ + static void backtracer(sos_vaddr_t PC, + sos_vaddr_t params, + sos_ui32_t depth, + void *custom_arg) + { + sos_ui32_t invalid = 0xffffffff, *arg1, *arg2, *arg3, *arg4; + + /* Get the address of the first 3 arguments from the + frame. Among these arguments, 0, 1, 2, 3 arguments might be + meaningful (depending on how many arguments the function may + take). */ + arg1 = (sos_ui32_t*)params; + arg2 = (sos_ui32_t*)(params+4); + arg3 = (sos_ui32_t*)(params+8); + arg4 = (sos_ui32_t*)(params+12); + + /* Make sure the addresses of these arguments fit inside the + stack boundaries */ +#define INTERVAL_OK(b,v,u) ( ((b) <= (sos_vaddr_t)(v)) \ + && ((sos_vaddr_t)(v) < (u)) ) + if (!INTERVAL_OK(stack_bottom, arg1, stack_bottom + stack_size)) + arg1 = &invalid; + if (!INTERVAL_OK(stack_bottom, arg2, stack_bottom + stack_size)) + arg2 = &invalid; + if (!INTERVAL_OK(stack_bottom, arg3, stack_bottom + stack_size)) + arg3 = &invalid; + if (!INTERVAL_OK(stack_bottom, arg4, stack_bottom + stack_size)) + arg4 = &invalid; + + /* Print the function context for this frame */ + if (on_bochs) + sos_bochs_printf("[%d] PC=0x%x arg1=0x%x arg2=0x%x arg3=0x%x\n", + (unsigned)depth, (unsigned)PC, + (unsigned)*arg1, (unsigned)*arg2, + (unsigned)*arg3); + + if (on_console) + sos_x86_videomem_printf(23-depth, 3, + SOS_X86_VIDEO_BG_BLUE + | SOS_X86_VIDEO_FG_LTGREEN, + "[%d] PC=0x%x arg1=0x%x arg2=0x%x arg3=0x%x arg4=0x%x", + (unsigned)depth, PC, + (unsigned)*arg1, (unsigned)*arg2, + (unsigned)*arg3, (unsigned)*arg4); + + } + sos_backtrace(cpu_state, 15, stack_bottom, stack_size, backtracer, NULL); +} + + +/* Page fault exception handler with demand paging for the kernel */ +static void pgflt_ex(int intid, const struct sos_cpu_state *ctxt) +{ + static sos_ui32_t demand_paging_count = 0; + sos_vaddr_t faulting_vaddr = sos_cpu_context_get_EX_faulting_vaddr(ctxt); + sos_paddr_t ppage_paddr; + + /* Check if address is covered by any VMM range */ + if (! sos_kmem_vmm_is_valid_vaddr(faulting_vaddr)) + { + /* No: The page fault is out of any kernel virtual region. For + the moment, we don't handle this. */ + dump_backtrace(ctxt, + bootstrap_stack_bottom, + bootstrap_stack_size, + TRUE, TRUE); + sos_display_fatal_error("Unresolved page Fault at instruction 0x%x on access to address 0x%x (info=%x)!", + sos_cpu_context_get_PC(ctxt), + (unsigned)faulting_vaddr, + (unsigned)sos_cpu_context_get_EX_info(ctxt)); + SOS_ASSERT_FATAL(! "Got page fault (note: demand paging is disabled)"); + } + + + /* + * Demand paging + */ + + /* Update the number of demand paging requests handled */ + demand_paging_count ++; + display_bits(0, 0, + SOS_X86_VIDEO_FG_LTRED | SOS_X86_VIDEO_BG_BLUE, + demand_paging_count); + + /* Allocate a new page for the virtual address */ + ppage_paddr = sos_physmem_ref_physpage_new(FALSE); + if (! ppage_paddr) + SOS_ASSERT_FATAL(! "TODO: implement swap. (Out of mem in demand paging because no swap for kernel yet !)"); + SOS_ASSERT_FATAL(SOS_OK == sos_paging_map(ppage_paddr, + SOS_PAGE_ALIGN_INF(faulting_vaddr), + FALSE, + SOS_VM_MAP_PROT_READ + | SOS_VM_MAP_PROT_WRITE + | SOS_VM_MAP_ATOMIC)); + sos_physmem_unref_physpage(ppage_paddr); + + /* Ok, we can now return to interrupted context */ +} + + + +/* ====================================================================== + * Demonstrate the use of the CPU kernet context management API: + * - A coroutine prints "Hlowrd" and switches to the other after each + * letter + * - A coroutine prints "el ol\n" and switches back to the other after + * each letter. + * The first to reach the '\n' returns back to main. + */ +struct sos_cpu_state *ctxt_hello1; +struct sos_cpu_state *ctxt_hello2; +struct sos_cpu_state *ctxt_main; +sos_vaddr_t hello1_stack, hello2_stack; + +static void reclaim_stack(sos_vaddr_t stack_vaddr) +{ + sos_kfree(stack_vaddr); +} + + +static void exit_hello12(sos_vaddr_t stack_vaddr) +{ + sos_cpu_context_exit_to(ctxt_main, + (sos_cpu_kstate_function_arg1_t*) reclaim_stack, + stack_vaddr); +} + + +static void hello1 (char *str) +{ + for ( ; *str != '\n' ; str++) + { + sos_bochs_printf("hello1: %c\n", *str); + sos_cpu_context_switch(& ctxt_hello1, ctxt_hello2); + } + + /* You can uncomment this in case you explicitly want to exit + now. But returning from the function will do the same */ + /* sos_cpu_context_exit_to(ctxt_main, + (sos_cpu_kstate_function_arg1_t*) reclaim_stack, + hello1_stack); */ +} + + +static void hello2 (char *str) +{ + for ( ; *str != '\n' ; str++) + { + sos_bochs_printf("hello2: %c\n", *str); + sos_cpu_context_switch(& ctxt_hello2, ctxt_hello1); + } + + /* You can uncomment this in case you explicitly want to exit + now. But returning from the function will do the same */ + /* sos_cpu_context_exit_to(ctxt_main, + (sos_cpu_kstate_function_arg1_t*) reclaim_stack, + hello2_stack); */ +} + + +void print_hello_world () +{ +#define DEMO_STACK_SIZE 1024 + /* Allocate the stacks */ + hello1_stack = sos_kmalloc(DEMO_STACK_SIZE, 0); + hello2_stack = sos_kmalloc(DEMO_STACK_SIZE, 0); + + /* Initialize the coroutines' contexts */ + sos_cpu_kstate_init(&ctxt_hello1, + (sos_cpu_kstate_function_arg1_t*) hello1, + (sos_ui32_t) "Hlowrd", + (sos_vaddr_t) hello1_stack, DEMO_STACK_SIZE, + (sos_cpu_kstate_function_arg1_t*) exit_hello12, + (sos_ui32_t) hello1_stack); + sos_cpu_kstate_init(&ctxt_hello2, + (sos_cpu_kstate_function_arg1_t*) hello2, + (sos_ui32_t) "el ol\n", + (sos_vaddr_t) hello2_stack, DEMO_STACK_SIZE, + (sos_cpu_kstate_function_arg1_t*) exit_hello12, + (sos_ui32_t) hello2_stack); + + /* Go to first coroutine */ + sos_bochs_printf("Printing Hello World\\n...\n"); + sos_cpu_context_switch(& ctxt_main, ctxt_hello1); + + /* The first coroutine to reach the '\n' switched back to us */ + sos_bochs_printf("Back in main !\n"); +} + + +/* ====================================================================== + * Generate page faults on an unmapped but allocated kernel virtual + * region, which results in a series of physical memory mappings for the + * faulted pages. + */ +static void test_demand_paging(int nb_alloc_vpages, int nb_alloc_ppages) +{ + int i; + sos_vaddr_t base_vaddr; + + sos_x86_videomem_printf(10, 0, + SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_LTGREEN, + "Demand paging test (alloc %dMB of VMM, test %dkB RAM)", + nb_alloc_vpages >> 8, nb_alloc_ppages << 2); + + /* Allocate virtual memory */ + base_vaddr = sos_kmem_vmm_alloc(nb_alloc_vpages, 0); + + SOS_ASSERT_FATAL(base_vaddr != (sos_vaddr_t)NULL); + sos_x86_videomem_printf(11, 0, + SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_YELLOW, + "Allocated virtual region [0x%x, 0x%x[", + base_vaddr, + base_vaddr + nb_alloc_vpages*SOS_PAGE_SIZE); + + /* Now use part of it in physical memory */ + for (i = 0 ; (i < nb_alloc_ppages) && (i < nb_alloc_vpages) ; i++) + { + /* Compute an address inside the range */ + sos_ui32_t *value, j; + sos_vaddr_t vaddr = base_vaddr; + vaddr += (nb_alloc_vpages - (i + 1))*SOS_PAGE_SIZE; + vaddr += 2345; + + sos_x86_videomem_printf(12, 0, + SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_YELLOW, + "Writing %d at virtual address 0x%x...", + i, vaddr); + + /* Write at this address */ + value = (sos_ui32_t*)vaddr; + *value = i; + + /* Yep ! A new page should normally have been allocated for us */ + sos_x86_videomem_printf(13, 0, + SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_YELLOW, + "Value read at address 0x%x = %d", + vaddr, (unsigned)*value); + } + + SOS_ASSERT_FATAL(SOS_OK == sos_kmem_vmm_free(base_vaddr)); + /* Yep ! A new page should normally have been allocated for us */ + sos_x86_videomem_printf(14, 0, + SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_YELLOW, + "Done (area un-allocated)"); +} + + + +/* ====================================================================== + * Shows how the backtrace stuff works + */ + +/* Recursive function. Print the backtrace from the innermost function */ +static void test_backtrace(int i, int magic, sos_vaddr_t stack_bottom, + sos_size_t stack_size) +{ + if (i <= 0) + { + /* The page fault exception handler will print the backtrace of + this function, because address 0x42 is not mapped */ + *((char*)0x42) = 12; + + /* More direct variant: */ + /* dump_backtrace(NULL, stack_bottom, stack_size, TRUE, TRUE); */ + } + else + test_backtrace(i-1, magic, stack_bottom, stack_size); +} + + +/* ====================================================================== + * Parsing of Mathematical expressions + * + * This is a recursive lexer/parser/evaluator for arithmetical + * expressions. Supports both binary +/-* and unary +- operators, as + * well as parentheses. + * + * Terminal tokens (Lexer): + * - Number: positive integer number + * - Variable: ascii name (regexp: [a-zA-Z]+) + * - Operator: +*-/ + * - Opening/closing parentheses + * + * Grammar (Parser): + * Expression ::= Term E' + * Expr_lr ::= + Term Expr_lr | - Term Expr_lr | Nothing + * Term ::= Factor Term_lr + * Term_lr ::= * Factor Term_lr | / Factor Term_lr | Nothing + * Factor ::= - Factor | + Factor | Scalar | ( Expression ) + * Scalar ::= Number | Variable + * + * Note. This is the left-recursive equivalent of the following basic grammar: + * Expression ::= Expression + Term | Expression - Term + * Term ::= Term * Factor | Term / Factor + * factor ::= - Factor | + Factor | Scalar | Variable | ( Expression ) + * Scalar ::= Number | Variable + * + * The parsing is composed of a 3 stages pipeline: + * - The reader: reads a string 1 character at a time, transferring + * the control back to lexer after each char. This function shows the + * interest in using coroutines, because its state (str) is + * implicitely stored in the stack between each iteration. + * - The lexer: consumes the characters from the reader and identifies + * the terminal tokens, 1 token at a time, transferring control back + * to the parser after each token. This function shows the interest + * in using coroutines, because its state (c and got_what_before) is + * implicitely stored in the stack between each iteration. + * - The parser: consumes the tokens from the lexer and builds the + * syntax tree of the expression. There is no real algorithmic + * interest in defining a coroutine devoted to do this. HOWEVER, we + * do use one for that because this allows us to switch to a much + * deeper stack. Actually, the parser is highly recursive, so that + * the default 16kB stack of the sos_main() function might not be + * enough. Here, we switch to a 64kB stack, which is safer for + * recursive functions. The Parser uses intermediary functions: these + * are defined and implemented as internal nested functions. This is + * just for the sake of clarity, and is absolutely not mandatory for + * the algorithm: one can transfer these functions out of the parser + * function without restriction. + * + * The evaluator is another recursive function that reuses the + * parser's stack to evaluate the parsed expression with the given + * values for the variables present in the expression. As for the + * parser function, this function defines and uses a nested function, + * which can be extracted from the main evaluation function at will. + * + * All these functions support a kind of "exception" feature: when + * something goes wrong, control is transferred DIRECTLY back to the + * sos_main() context, without unrolling the recursions. This shows + * how exceptions basically work, but one should not consider this as + * a reference exceptions implementation. Real exception mechanisms + * (such as that in the C++ language) call the destructors to the + * objects allocated on the stack during the "stack unwinding" process + * upon exception handling, which complicates a lot the mechanism. We + * don't have real Objects here (in the OOP sense, full-featured with + * destructors), so we don't have to complicate things. + * + * After this little coroutine demo, one should forget all about such + * a low-level manual direct manipulation of stacks. This would + * probably mess up the whole kernel to do what we do here (locked + * resources such as mutex/semaphore won't be correctly unlocked, + * ...). Higher level "kernel thread" primitives will soon be + * presented, which provide a higher-level set of APIs to manage CPU + * contexts. You'll have to use EXCLUSIVELY those APIs. If you still + * need a huge stack to do recursion for example, please don't even + * think of changing manually the stack for something bigger ! Simply + * rethink your algorithm, making it non-recursive. + */ + + +/* The stacks involved */ +static char stack_reader[1024]; +static char stack_lexer[1024]; +static char deep_stack[65536]; /* For the parser and the evaluator */ + +/* The CPU states for the various coroutines */ +static struct sos_cpu_state *st_reader, *st_lexer, *st_parser, + *st_eval, *st_free, *st_main; + + +/* + * Default exit/reclaim functions: return control to the "sos_main()" + * context + */ +static void reclaim(int unused) +{ +} +static void func_exit(sos_ui32_t unused) +{ + sos_cpu_context_exit_to(st_main, (sos_cpu_kstate_function_arg1_t*)reclaim, 0); +} + + +/* + * The reader coroutine and associated variable. This coroutine could + * have been a normal function, except that the current parsed + * character would have to be stored somewhere. + */ +static char data_reader_to_lexer; + +static void func_reader(const char *str) +{ + for ( ; str && (*str != '\0') ; str++) + { + data_reader_to_lexer = *str; + sos_cpu_context_switch(& st_reader, st_lexer); + } + + data_reader_to_lexer = '\0'; + sos_cpu_context_switch(& st_reader, st_lexer); +} + + +/* + * The Lexer coroutine and associated types/variables. This coroutine + * could have been a normal function, except that the current parsed + * character, token and previous token would have to be stored + * somewhere. + */ +#define STR_VAR_MAXLEN 16 +static struct lex_elem +{ + enum { LEX_IS_NUMBER, LEX_IS_OPER, LEX_IS_VAR, + LEX_IS_OPENPAR, LEX_IS_CLOSEPAR, LEX_END } type; + union { + int number; + char operator; + char var[STR_VAR_MAXLEN]; + }; +} data_lexer_to_parser; + +static void func_lexer(sos_ui32_t unused) +{ + char c; + enum { GOT_SPACE, GOT_NUM, GOT_OP, GOT_STR, + GOT_OPENPAR, GOT_CLOSEPAR } got_what, got_what_before; + + data_lexer_to_parser.number = 0; + got_what_before = GOT_SPACE; + do + { + /* Consume one character from the reader */ + sos_cpu_context_switch(& st_lexer, st_reader); + c = data_reader_to_lexer; + + /* Classify the consumed character */ + if ( (c >= '0') && (c <= '9') ) + got_what = GOT_NUM; + else if ( (c == '+') || (c == '-') || (c == '*') || (c == '/') ) + got_what = GOT_OP; + else if ( ( (c >= 'a') && (c <= 'z') ) + || ( (c >= 'A') && (c <= 'Z') ) ) + got_what = GOT_STR; + else if (c == '(') + got_what = GOT_OPENPAR; + else if (c == ')') + got_what = GOT_CLOSEPAR; + else + got_what = GOT_SPACE; + + /* Determine whether the current token is ended */ + if ( (got_what != got_what_before) + || (got_what_before == GOT_OP) + || (got_what_before == GOT_OPENPAR) + || (got_what_before == GOT_CLOSEPAR) ) + { + /* return control back to the parser if the previous token + has been recognized */ + if ( (got_what_before != GOT_SPACE) ) + sos_cpu_context_switch(& st_lexer, st_parser); + + data_lexer_to_parser.number = 0; + } + + /* Update the token being currently recognized */ + if (got_what == GOT_OP) + { + data_lexer_to_parser.type = LEX_IS_OPER; + data_lexer_to_parser.operator = c; + } + else if (got_what == GOT_NUM) + { + data_lexer_to_parser.type = LEX_IS_NUMBER; + data_lexer_to_parser.number *= 10; + data_lexer_to_parser.number += (c - '0'); + } + else if (got_what == GOT_STR) + { + char to_cat[] = { c, '\0' }; + data_lexer_to_parser.type = LEX_IS_VAR; + strzcat(data_lexer_to_parser.var, to_cat, STR_VAR_MAXLEN); + } + else if (got_what == GOT_OPENPAR) + data_lexer_to_parser.type = LEX_IS_OPENPAR; + else if (got_what == GOT_CLOSEPAR) + data_lexer_to_parser.type = LEX_IS_CLOSEPAR; + + got_what_before = got_what; + } + while (c != '\0'); + + /* Transfer last recognized token to the parser */ + if ( (got_what_before != GOT_SPACE) ) + sos_cpu_context_switch(& st_lexer, st_parser); + + /* Signal that no more token are available */ + data_lexer_to_parser.type = LEX_END; + sos_cpu_context_switch(& st_lexer, st_parser); + + /* Exception: parser asks for a token AFTER having received the last + one */ + sos_bochs_printf("Error: end of string already reached !\n"); + sos_cpu_context_switch(& st_lexer, st_main); +} + + +/* + * The Parser coroutine and associated types/variables + */ +struct syntax_node +{ + enum { YY_IS_BINOP, YY_IS_UNAROP, YY_IS_NUM, YY_IS_VAR } type; + union + { + int number; + char var[STR_VAR_MAXLEN]; + struct + { + char op; + struct syntax_node *parm_left, *parm_right; + } binop; + struct + { + char op; + struct syntax_node *parm; + } unarop; + }; +}; + +static void func_parser(struct syntax_node ** syntax_tree) +{ + static struct syntax_node *alloc_node_num(int val); + static struct syntax_node *alloc_node_var(const char * name); + static struct syntax_node *alloc_node_binop(char op, + struct syntax_node *parm_left, + struct syntax_node *parm_right); + static struct syntax_node *alloc_node_unarop(char op, + struct syntax_node *parm); + static struct syntax_node * get_expr(); + static struct syntax_node * get_expr_lr(struct syntax_node *n); + static struct syntax_node * get_term(); + static struct syntax_node * get_term_lr(struct syntax_node *n); + static struct syntax_node * get_factor(); + static struct syntax_node * get_scalar(); + + /* Create a new node to store a number */ + static struct syntax_node *alloc_node_num(int val) + { + struct syntax_node *n + = (struct syntax_node*) sos_kmalloc(sizeof(struct syntax_node), 0); + n->type = YY_IS_NUM; + n->number = val; + return n; + } + /* Create a new node to store a variable */ + static struct syntax_node *alloc_node_var(const char * name) + { + struct syntax_node *n + = (struct syntax_node*) sos_kmalloc(sizeof(struct syntax_node), 0); + n->type = YY_IS_VAR; + strzcpy(n->var, name, STR_VAR_MAXLEN); + return n; + } + /* Create a new node to store a binary operator */ + static struct syntax_node *alloc_node_binop(char op, + struct syntax_node *parm_left, + struct syntax_node *parm_right) + { + struct syntax_node *n + = (struct syntax_node*) sos_kmalloc(sizeof(struct syntax_node), 0); + n->type = YY_IS_BINOP; + n->binop.op = op; + n->binop.parm_left = parm_left; + n->binop.parm_right = parm_right; + return n; + } + /* Create a new node to store a unary operator */ + static struct syntax_node *alloc_node_unarop(char op, + struct syntax_node *parm) + { + struct syntax_node *n + = (struct syntax_node*) sos_kmalloc(sizeof(struct syntax_node), 0); + n->type = YY_IS_UNAROP; + n->unarop.op = op; + n->unarop.parm = parm; + return n; + } + + /* Raise an exception: transfer control back to main context, + without unrolling the whole recursion */ + static void parser_exception(const char *str) + { + sos_bochs_printf("Parser exception: %s\n", str); + sos_cpu_context_switch(& st_parser, st_main); + } + + /* Consume the current terminal "number" token and ask for a new + token */ + static int get_number() + { + int v; + if (data_lexer_to_parser.type != LEX_IS_NUMBER) + parser_exception("Expected number"); + v = data_lexer_to_parser.number; + sos_cpu_context_switch(& st_parser, st_lexer); + return v; + } + /* Consume the current terminal "variable" token and ask for a new + token */ + static void get_str(char name[STR_VAR_MAXLEN]) + { + if (data_lexer_to_parser.type != LEX_IS_VAR) + parser_exception("Expected variable"); + strzcpy(name, data_lexer_to_parser.var, STR_VAR_MAXLEN); + sos_cpu_context_switch(& st_parser, st_lexer); + } + /* Consume the current terminal "operator" token and ask for a new + token */ + static char get_op() + { + char op; + if (data_lexer_to_parser.type != LEX_IS_OPER) + parser_exception("Expected operator"); + op = data_lexer_to_parser.operator; + sos_cpu_context_switch(& st_parser, st_lexer); + return op; + } + /* Consume the current terminal "parenthese" token and ask for a new + token */ + static void get_par() + { + if ( (data_lexer_to_parser.type != LEX_IS_OPENPAR) + && (data_lexer_to_parser.type != LEX_IS_CLOSEPAR) ) + parser_exception("Expected parenthese"); + sos_cpu_context_switch(& st_parser, st_lexer); + } + + /* Parse an Expression */ + static struct syntax_node * get_expr() + { + struct syntax_node *t = get_term(); + return get_expr_lr(t); + } + /* Parse an Expr_lr */ + static struct syntax_node * get_expr_lr(struct syntax_node *n) + { + if ( (data_lexer_to_parser.type == LEX_IS_OPER) + && ( (data_lexer_to_parser.operator == '+') + || (data_lexer_to_parser.operator == '-') ) ) + { + char op = get_op(); + struct syntax_node *term = get_term(); + struct syntax_node *node_op = alloc_node_binop(op, n, term); + return get_expr_lr(node_op); + } + return n; + } + /* Parse a Term */ + static struct syntax_node * get_term() + { + struct syntax_node *f1 = get_factor(); + return get_term_lr(f1); + } + /* Parse a Term_lr */ + static struct syntax_node * get_term_lr(struct syntax_node *n) + { + if ( (data_lexer_to_parser.type == LEX_IS_OPER) + && ( (data_lexer_to_parser.operator == '*') + || (data_lexer_to_parser.operator == '/') ) ) + { + char op = get_op(); + struct syntax_node *factor = get_factor(); + struct syntax_node *node_op = alloc_node_binop(op, n, factor); + return get_term_lr(node_op); + } + return n; + } + /* Parse a Factor */ + static struct syntax_node * get_factor() + { + if ( (data_lexer_to_parser.type == LEX_IS_OPER) + && ( (data_lexer_to_parser.operator == '-') + || (data_lexer_to_parser.operator == '+') ) ) + { char op = data_lexer_to_parser.operator; + get_op(); return alloc_node_unarop(op, get_factor()); } + else if (data_lexer_to_parser.type == LEX_IS_OPENPAR) + { + struct syntax_node *expr; + get_par(); + expr = get_expr(); + if (data_lexer_to_parser.type != LEX_IS_CLOSEPAR) + parser_exception("Mismatched parentheses"); + get_par(); + return expr; + } + + return get_scalar(); + } + /* Parse a Scalar */ + static struct syntax_node * get_scalar() + { + if (data_lexer_to_parser.type != LEX_IS_NUMBER) + { + char var[STR_VAR_MAXLEN]; + get_str(var); + return alloc_node_var(var); + } + return alloc_node_num(get_number()); + } + + + /* + * Body of the function + */ + + /* Get the first token */ + sos_cpu_context_switch(& st_parser, st_lexer); + + /* Begin the parsing ! */ + *syntax_tree = get_expr(); + /* The result is returned in the syntax_tree parameter */ +} + + +/* + * Setup the parser's pipeline + */ +static struct syntax_node * parse_expression(const char *expr) +{ + struct syntax_node *retval = NULL; + + /* Build the context of the functions in the pipeline */ + sos_cpu_kstate_init(& st_reader, + (sos_cpu_kstate_function_arg1_t*)func_reader, + (sos_ui32_t)expr, + (sos_vaddr_t)stack_reader, sizeof(stack_reader), + (sos_cpu_kstate_function_arg1_t*)func_exit, 0); + sos_cpu_kstate_init(& st_lexer, + (sos_cpu_kstate_function_arg1_t*)func_lexer, + 0, + (sos_vaddr_t)stack_lexer, sizeof(stack_lexer), + (sos_cpu_kstate_function_arg1_t*)func_exit, 0); + sos_cpu_kstate_init(& st_parser, + (sos_cpu_kstate_function_arg1_t*)func_parser, + (sos_ui32_t) /* syntax tree ! */&retval, + (sos_vaddr_t)deep_stack, sizeof(deep_stack), + (sos_cpu_kstate_function_arg1_t*)func_exit, 0); + + /* Parse the expression */ + sos_cpu_context_switch(& st_main, st_parser); + return retval; +} + + +/* + * The Evaluator coroutine and associated types/variables + */ +struct func_eval_params +{ + const struct syntax_node *e; + const char **var_name; + int *var_val; + int nb_vars; + + int result; +}; + +static void func_eval(struct func_eval_params *parms) +{ + /* The internal (recursive) nested function to evaluate each node of + the syntax tree */ + static int rec_eval(const struct syntax_node *n, + const char* var_name[], int var_val[], int nb_vars) + { + switch (n->type) + { + case YY_IS_NUM: + return n->number; + + case YY_IS_VAR: + { + int i; + for (i = 0 ; i < nb_vars ; i++) + if (0 == strcmp(var_name[i], n->var)) + return var_val[i]; + + /* Exception: no variable with that name ! */ + sos_bochs_printf("ERROR: unknown variable %s\n", n->var); + sos_cpu_context_switch(& st_eval, st_main); + } + + case YY_IS_BINOP: + { + int left = rec_eval(n->binop.parm_left, + var_name, var_val, nb_vars); + int right = rec_eval(n->binop.parm_right, + var_name, var_val, nb_vars); + switch (n->binop.op) + { + case '+': return left + right; + case '-': return left - right; + case '*': return left * right; + case '/': return left / right; + default: + /* Exception: no such operator (INTERNAL error) ! */ + sos_bochs_printf("ERROR: unknown binop %c\n", n->binop.op); + sos_cpu_context_switch(& st_eval, st_main); + } + } + + case YY_IS_UNAROP: + { + int arg = rec_eval(n->unarop.parm, var_name, var_val, nb_vars); + switch (n->unarop.op) + { + case '-': return -arg; + case '+': return arg; + default: + /* Exception: no such operator (INTERNAL error) ! */ + sos_bochs_printf("ERROR: unknown unarop %c\n", n->unarop.op); + sos_cpu_context_switch(& st_eval, st_main); + } + } + } + + /* Exception: no such syntax node (INTERNAL error) ! */ + sos_bochs_printf("ERROR: invalid node type\n"); + sos_cpu_context_switch(& st_eval, st_main); + return -1; /* let's make gcc happy */ + } + + + /* + * Function BODY + */ + /* Update p.result returned back to calling function */ + parms->result + = rec_eval(parms->e, parms->var_name, parms->var_val, parms->nb_vars); +} + +/* + * Change the stack for something larger in order to call the + * recursive function above in a safe way + */ +static int eval_expression(const struct syntax_node *e, + const char* var_name[], int var_val[], int nb_vars) +{ + struct func_eval_params p + = (struct func_eval_params){ .e=e, + .var_name=var_name, + .var_val=var_val, + .nb_vars=nb_vars, + .result = 0 }; + + sos_cpu_kstate_init(& st_eval, + (sos_cpu_kstate_function_arg1_t*)func_eval, + (sos_ui32_t)/* p.result is modified upon success */&p, + (sos_vaddr_t)deep_stack, sizeof(deep_stack), + (sos_cpu_kstate_function_arg1_t*)func_exit, 0); + + /* Go ! */ + sos_cpu_context_switch(& st_main, st_eval); + return p.result; +} + + +/* + * Function to free the syntax tree + */ +static void func_free(struct syntax_node *n) +{ + switch (n->type) + { + case YY_IS_NUM: + case YY_IS_VAR: + break; + + case YY_IS_BINOP: + func_free(n->binop.parm_left); + func_free(n->binop.parm_right); + break; + + case YY_IS_UNAROP: + func_free(n->unarop.parm); + break; + } + + sos_kfree((sos_vaddr_t)n); +} + +/* + * Change the stack for something larger in order to call the + * recursive function above in a safe way + */ +static void free_syntax_tree(struct syntax_node *tree) +{ + sos_cpu_kstate_init(& st_free, + (sos_cpu_kstate_function_arg1_t*)func_free, + (sos_ui32_t)tree, + (sos_vaddr_t)deep_stack, sizeof(deep_stack), + (sos_cpu_kstate_function_arg1_t*)func_exit, 0); + + /* Go ! */ + sos_cpu_context_switch(& st_main, st_free); +} + + +/* ====================================================================== + * The C entry point of our operating system + */ +void sos_main(unsigned long magic, unsigned long addr) +{ + unsigned i; + sos_paddr_t sos_kernel_core_base_paddr, sos_kernel_core_top_paddr; + struct syntax_node *syntax_tree; + + /* Grub sends us a structure, called multiboot_info_t with a lot of + precious informations about the system, see the multiboot + documentation for more information. */ + multiboot_info_t *mbi; + mbi = (multiboot_info_t *) addr; + + /* Setup bochs and console, and clear the console */ + sos_bochs_setup(); + + sos_x86_videomem_setup(); + sos_x86_videomem_cls(SOS_X86_VIDEO_BG_BLUE); + + /* Greetings from SOS */ + if (magic == MULTIBOOT_BOOTLOADER_MAGIC) + /* Loaded with Grub */ + sos_x86_videomem_printf(1, 0, + SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE, + "Welcome From GRUB to %s%c RAM is %dMB (upper mem = 0x%x kB)", + "SOS article 6", ',', + (unsigned)(mbi->mem_upper >> 10) + 1, + (unsigned)mbi->mem_upper); + else + /* Not loaded with grub */ + sos_x86_videomem_printf(1, 0, + SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE, + "Welcome to SOS article 6"); + + sos_bochs_putstring("Message in a bochs: This is SOS article 6.\n"); + + /* Setup CPU segmentation and IRQ subsystem */ + sos_gdt_subsystem_setup(); + sos_idt_subsystem_setup(); + + /* Setup SOS IRQs and exceptions subsystem */ + sos_exception_subsystem_setup(); + sos_irq_subsystem_setup(); + + /* Configure the timer so as to raise the IRQ0 at a 100Hz rate */ + sos_i8254_set_frequency(100); + + /* We need a multiboot-compliant boot loader to get the size of the RAM */ + if (magic != MULTIBOOT_BOOTLOADER_MAGIC) + { + sos_x86_videomem_putstring(20, 0, + SOS_X86_VIDEO_FG_LTRED + | SOS_X86_VIDEO_BG_BLUE + | SOS_X86_VIDEO_FG_BLINKING, + "I'm not loaded with Grub !"); + /* STOP ! */ + for (;;) + continue; + } + + /* + * Some interrupt handlers + */ + + /* Binding some HW interrupts and exceptions to software routines */ + sos_irq_set_routine(SOS_IRQ_TIMER, + clk_it); + + /* + * Setup physical memory management + */ + + /* Multiboot says: "The value returned for upper memory is maximally + the address of the first upper memory hole minus 1 megabyte.". It + also adds: "It is not guaranteed to be this value." aka "YMMV" ;) */ + sos_physmem_subsystem_setup((mbi->mem_upper<<10) + (1<<20), + & sos_kernel_core_base_paddr, + & sos_kernel_core_top_paddr); + + /* + * Switch to paged-memory mode + */ + + /* Disabling interrupts should seem more correct, but it's not really + necessary at this stage */ + SOS_ASSERT_FATAL(SOS_OK == + sos_paging_subsystem_setup(sos_kernel_core_base_paddr, + sos_kernel_core_top_paddr)); + + /* Bind the page fault exception */ + sos_exception_set_routine(SOS_EXCEPT_PAGE_FAULT, + pgflt_ex); + + /* + * Setup kernel virtual memory allocator + */ + + if (sos_kmem_vmm_subsystem_setup(sos_kernel_core_base_paddr, + sos_kernel_core_top_paddr, + bootstrap_stack_bottom, + bootstrap_stack_bottom + + bootstrap_stack_size)) + sos_bochs_printf("Could not setup the Kernel virtual space allocator\n"); + + if (sos_kmalloc_subsystem_setup()) + sos_bochs_printf("Could not setup the Kmalloc subsystem\n"); + + /* + * Enabling the HW interrupts here, this will make the timer HW + * interrupt call our clk_it handler + */ + asm volatile ("sti\n"); + + /* + * Print hello world using coroutines + */ + print_hello_world(); + + + /* + * Run coroutine tests + */ + sos_x86_videomem_printf(4, 0, + SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_LTGREEN, + "Coroutine test"); + sos_x86_videomem_printf(5, 0, + SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_YELLOW, + "Parsing..."); + syntax_tree = parse_expression(" - ( (69/ toto)+ ( (( - +-- 1))) + --toto*((toto+ - - y - +2*(y-toto))*y) +2*(y-toto) )/- (( y - toto)*2)"); + + if (syntax_tree != NULL) + { + sos_x86_videomem_printf(6, 0, + SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_YELLOW, + "Evaluating..."); + sos_x86_videomem_printf(7, 0, + SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_YELLOW, + "Result=%d (if 0: check bochs output)", + eval_expression(syntax_tree, + (const char*[]){"toto", "y"}, + (int[]){3, 4}, + 2)); + free_syntax_tree(syntax_tree); + sos_x86_videomem_printf(8, 0, + SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_YELLOW, + "Done (un-allocated syntax tree)"); + } + else + { + sos_x86_videomem_printf(6, 0, + SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_YELLOW, + "Error in parsing (see bochs output)"); + } + + /* + * Run some demand-paging tests + */ + test_demand_paging(234567, 500); + + + /* + * Create an un-resolved page fault, which will make the page fault + * handler print the backtrace. + */ + test_backtrace(6, 0xdeadbeef, bootstrap_stack_bottom, bootstrap_stack_size); + + /* + * System should be halted BEFORE here ! + */ + + + /* An operatig system never ends */ + for (;;) + { + /* Remove this instruction if you get an "Invalid opcode" CPU + exception (old 80386 CPU) */ + asm("hlt\n"); + + continue; + } +} diff --git a/sos-code-article6/sos/physmem.c b/sos-code-article6/sos/physmem.c new file mode 100644 index 0000000..daf730f --- /dev/null +++ b/sos-code-article6/sos/physmem.c @@ -0,0 +1,319 @@ +/* Copyright (C) 2004 David Decotigny + Copyright (C) 2000 The KOS Team + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#include <sos/list.h> +#include <sos/macros.h> +#include <sos/assert.h> +#include <sos/klibc.h> + +#include "physmem.h" + +/** A descriptor for a physical page in SOS */ +struct physical_page_descr +{ + /** The physical base address for the page */ + sos_paddr_t paddr; + + /** The reference count for this physical page. > 0 means that the + page is in the used list. */ + sos_count_t ref_cnt; + + /** Some data associated with the page when it is mapped in kernel space */ + struct sos_kmem_range *kernel_range; + + /** The other pages on the list (used, free) */ + struct physical_page_descr *prev, *next; +}; + +/** These are some markers present in the executable file (see sos.lds) */ +extern char __b_kernel, __e_kernel; + +/** The array of ppage descriptors will be located at this address */ +#define PAGE_DESCR_ARRAY_ADDR \ + SOS_PAGE_ALIGN_SUP((sos_paddr_t) (& __e_kernel)) +static struct physical_page_descr * physical_page_descr_array; + +/** The list of physical pages currently available */ +static struct physical_page_descr *free_ppage; + +/** The list of physical pages currently in use */ +static struct physical_page_descr *used_ppage; + +/** We will store here the interval of valid physical addresses */ +static sos_paddr_t physmem_base, physmem_top; + +/** We store the number of pages used/free */ +static sos_count_t physmem_total_pages, physmem_used_pages; + +sos_ret_t sos_physmem_subsystem_setup(sos_size_t ram_size, + /* out */sos_paddr_t *kernel_core_base, + /* out */sos_paddr_t *kernel_core_top) +{ + /* The iterator over the page descriptors */ + struct physical_page_descr *ppage_descr; + + /* The iterator over the physical addresses */ + sos_paddr_t ppage_addr; + + /* Make sure ram size is aligned on a page boundary */ + ram_size = SOS_PAGE_ALIGN_INF(ram_size);/* Yes, we may lose at most a page */ + + /* Reset the used/free page lists before building them */ + free_ppage = used_ppage = NULL; + physmem_total_pages = physmem_used_pages = 0; + + /* Make sure that there is enough memory to store the array of page + descriptors */ + *kernel_core_base = SOS_PAGE_ALIGN_INF((sos_paddr_t)(& __b_kernel)); + *kernel_core_top + = PAGE_DESCR_ARRAY_ADDR + + SOS_PAGE_ALIGN_SUP( (ram_size >> SOS_PAGE_SHIFT) + * sizeof(struct physical_page_descr)); + if (*kernel_core_top > ram_size) + return -SOS_ENOMEM; + + /* Page 0-4kB is not available in order to return address 0 as a + means to signal "no page available" */ + physmem_base = SOS_PAGE_SIZE; + physmem_top = ram_size; + + /* Setup the page descriptor arrray */ + physical_page_descr_array + = (struct physical_page_descr*)PAGE_DESCR_ARRAY_ADDR; + + /* Scan the list of physical pages */ + for (ppage_addr = 0, + ppage_descr = physical_page_descr_array ; + ppage_addr < physmem_top ; + ppage_addr += SOS_PAGE_SIZE, + ppage_descr ++) + { + enum { PPAGE_MARK_RESERVED, PPAGE_MARK_FREE, + PPAGE_MARK_KERNEL, PPAGE_MARK_HWMAP } todo; + + memset(ppage_descr, 0x0, sizeof(struct physical_page_descr)); + + /* Init the page descriptor for this page */ + ppage_descr->paddr = ppage_addr; + + /* Reserved : 0 ... base */ + if (ppage_addr < physmem_base) + todo = PPAGE_MARK_RESERVED; + + /* Free : base ... BIOS */ + else if ((ppage_addr >= physmem_base) + && (ppage_addr < BIOS_N_VIDEO_START)) + todo = PPAGE_MARK_FREE; + + /* Used : BIOS */ + else if ((ppage_addr >= BIOS_N_VIDEO_START) + && (ppage_addr < BIOS_N_VIDEO_END)) + todo = PPAGE_MARK_HWMAP; + + /* Free : BIOS ... kernel */ + else if ((ppage_addr >= BIOS_N_VIDEO_END) + && (ppage_addr < (sos_paddr_t) (& __b_kernel))) + todo = PPAGE_MARK_FREE; + + /* Used : Kernel code/data/bss + physcal page descr array */ + else if ((ppage_addr >= *kernel_core_base) + && (ppage_addr < *kernel_core_top)) + todo = PPAGE_MARK_KERNEL; + + /* Free : first page of descr ... end of RAM */ + else + todo = PPAGE_MARK_FREE; + + /* Actually does the insertion in the used/free page lists */ + physmem_total_pages ++; + switch (todo) + { + case PPAGE_MARK_FREE: + ppage_descr->ref_cnt = 0; + list_add_head(free_ppage, ppage_descr); + break; + + case PPAGE_MARK_KERNEL: + case PPAGE_MARK_HWMAP: + ppage_descr->ref_cnt = 1; + list_add_head(used_ppage, ppage_descr); + physmem_used_pages ++; + break; + + default: + /* Reserved page: nop */ + break; + } + } + + return SOS_OK; +} + + +sos_paddr_t sos_physmem_ref_physpage_new(sos_bool_t can_block) +{ + struct physical_page_descr *ppage_descr; + + if (! free_ppage) + return (sos_paddr_t)NULL; + + /* Retrieve a page in the free list */ + ppage_descr = list_pop_head(free_ppage); + + /* The page is assumed not to be already used */ + SOS_ASSERT_FATAL(ppage_descr->ref_cnt == 0); + + /* Mark the page as used (this of course sets the ref count to 1) */ + ppage_descr->ref_cnt ++; + + /* No associated kernel range by default */ + ppage_descr->kernel_range = NULL; + + /* Put the page in the used list */ + list_add_tail(used_ppage, ppage_descr); + physmem_used_pages ++; + + return ppage_descr->paddr; +} + + +/** + * Helper function to get the physical page descriptor for the given + * physical page address. + * + * @return NULL when out-of-bounds or non-page-aligned + */ +inline static struct physical_page_descr * +get_page_descr_at_paddr(sos_paddr_t ppage_paddr) +{ + /* Don't handle non-page-aligned addresses */ + if (ppage_paddr & SOS_PAGE_MASK) + return NULL; + + /* Don't support out-of-bounds requests */ + if ((ppage_paddr < physmem_base) || (ppage_paddr >= physmem_top)) + return NULL; + + return physical_page_descr_array + (ppage_paddr >> SOS_PAGE_SHIFT); +} + + +sos_ret_t sos_physmem_ref_physpage_at(sos_paddr_t ppage_paddr) +{ + struct physical_page_descr *ppage_descr + = get_page_descr_at_paddr(ppage_paddr); + + if (! ppage_descr) + return -SOS_EINVAL; + + /* Increment the reference count for the page */ + ppage_descr->ref_cnt ++; + + /* If the page is newly referenced (ie we are the only owners of the + page => ref cnt == 1), transfer it in the used pages list */ + if (ppage_descr->ref_cnt == 1) + { + list_delete(free_ppage, ppage_descr); + + /* No associated kernel range by default */ + ppage_descr->kernel_range = NULL; + + list_add_tail(used_ppage, ppage_descr); + physmem_used_pages ++; + + /* The page is newly referenced */ + return FALSE; + } + + /* The page was already referenced by someone */ + return TRUE; +} + + +sos_ret_t +sos_physmem_unref_physpage(sos_paddr_t ppage_paddr) +{ + /* By default the return value indicates that the page is still + used */ + sos_ret_t retval = FALSE; + + struct physical_page_descr *ppage_descr + = get_page_descr_at_paddr(ppage_paddr); + + if (! ppage_descr) + return -SOS_EINVAL; + + /* Don't do anything if the page is not in the used list */ + if (ppage_descr->ref_cnt <= 0) + return -SOS_EINVAL; + + /* Unreference the page, and, when no mapping is active anymore, put + the page in the free list */ + ppage_descr->ref_cnt--; + if (ppage_descr->ref_cnt <= 0) + { + /* Reset associated kernel range */ + ppage_descr->kernel_range = NULL; + + /* Transfer the page, considered USED, to the free list */ + list_delete(used_ppage, ppage_descr); + physmem_used_pages --; + list_add_head(free_ppage, ppage_descr); + + /* Indicate that the page is now unreferenced */ + retval = TRUE; + } + + return retval; +} + + +struct sos_kmem_range* sos_physmem_get_kmem_range(sos_paddr_t ppage_paddr) +{ + struct physical_page_descr *ppage_descr + = get_page_descr_at_paddr(ppage_paddr); + + if (! ppage_descr) + return NULL; + + return ppage_descr->kernel_range; +} + + +sos_ret_t sos_physmem_set_kmem_range(sos_paddr_t ppage_paddr, + struct sos_kmem_range *range) +{ + struct physical_page_descr *ppage_descr + = get_page_descr_at_paddr(ppage_paddr); + + if (! ppage_descr) + return -SOS_EINVAL; + + ppage_descr->kernel_range = range; + return SOS_OK; +} + +sos_ret_t sos_physmem_get_state(/* out */sos_count_t *total_ppages, + /* out */sos_count_t *used_ppages) +{ + if (total_ppages) + *total_ppages = physmem_total_pages; + if (used_ppages) + *used_ppages = physmem_used_pages; + return SOS_OK; +} diff --git a/sos-code-article6/sos/physmem.h b/sos-code-article6/sos/physmem.h new file mode 100644 index 0000000..7b4cd2b --- /dev/null +++ b/sos-code-article6/sos/physmem.h @@ -0,0 +1,147 @@ +/* Copyright (C) 2004 David Decotigny + Copyright (C) 2000 The KOS Team + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#ifndef _SOS_PHYSMEM_H_ +#define _SOS_PHYSMEM_H_ + +/** + * @file physmem.h + * + * Physical pages of memory + */ + +#include <sos/errno.h> +#include <sos/types.h> +#include <sos/macros.h> + +/** The size of a physical page (arch-dependent) */ +#define SOS_PAGE_SIZE (4*1024) + +/** The corresponding shift */ +#define SOS_PAGE_SHIFT 12 /* 4 kB = 2^12 B */ + +/** The corresponding mask */ +#define SOS_PAGE_MASK ((1<<12) - 1) + +#define SOS_PAGE_ALIGN_INF(val) \ + SOS_ALIGN_INF((val), SOS_PAGE_SIZE) +#define SOS_PAGE_ALIGN_SUP(val) \ + SOS_ALIGN_SUP((val), SOS_PAGE_SIZE) +#define SOS_IS_PAGE_ALIGNED(val) \ + SOS_IS_ALIGNED((val), SOS_PAGE_SIZE) + +/** + * This is the reserved physical interval for the x86 video memory and + * BIOS area. In physmem.c, we have to mark this area as "used" in + * order to prevent from allocating it. And in paging.c, we'd better + * map it in virtual space if we really want to be able to print to + * the screen (for debugging purpose, at least): for this, the + * simplest is to identity-map this area in virtual space (note + * however that this mapping could also be non-identical). + */ +#define BIOS_N_VIDEO_START 0xa0000 +#define BIOS_N_VIDEO_END 0x100000 + + +/** + * Initialize the physical memory subsystem, for the physical area [0, + * ram_size). This routine takes into account the BIOS and video + * areas, to prevent them from future allocations. + * + * @param ram_size The size of the RAM that will be managed by this subsystem + * + * @param kernel_core_base The lowest address for which the kernel + * assumes identity mapping (ie virtual address == physical address) + * will be stored here + * + * @param kernel_core_top The top address for which the kernel + * assumes identity mapping (ie virtual address == physical address) + * will be stored here + */ +sos_ret_t sos_physmem_subsystem_setup(sos_size_t ram_size, + /* out */sos_paddr_t *kernel_core_base, + /* out */sos_paddr_t *kernel_core_top); + +/** + * Retrieve the total number of pages, and the number of free pages + */ +sos_ret_t sos_physmem_get_state(/* out */sos_count_t *total_ppages, + /* out */sos_count_t *used_ppages); + + +/** + * Get a free page. + * + * @return The (physical) address of the (physical) page allocated, or + * NULL when none currently available. + * + * @param can_block TRUE if the function is allowed to block + * @note The page returned has a reference count equal to 1. + */ +sos_paddr_t sos_physmem_ref_physpage_new(sos_bool_t can_block); + + +/** + * Increment the reference count of a given physical page. Useful for + * VM code which tries to map a precise physical address. + * + * @param ppage_paddr Physical address of the page (MUST be page-aligned) + * + * @return TRUE when the page was previously in use, FALSE when the + * page was previously in the free list, <0 when the page address is + * invalid. + */ +sos_ret_t sos_physmem_ref_physpage_at(sos_paddr_t ppage_paddr); + + +/** + * Decrement the reference count of the given physical page. When this + * reference count reaches 0, the page is marked free, ie is available + * for future sos_physmem_get_physpage() + * + * @param ppage_paddr Physical address of the page (MUST be page-aligned) + * + * @return FALSE when the page is still in use, TRUE when the page is now + * unreferenced, <0 when the page address is invalid + */ +sos_ret_t sos_physmem_unref_physpage(sos_paddr_t ppage_paddr); + + +#include <sos/kmem_vmm.h> + +/** + * Return the kernel memory allocation range associated with the given + * physical page, or NULL when page has no associated range + * + * @param ppage_paddr Physical address of the page (MUST be page-aligned) + */ +struct sos_kmem_range* sos_physmem_get_kmem_range(sos_paddr_t ppage_paddr); + + +/** + * Set the kernel memory allocation range associated to the given + * physical page. + * + * @param ppage_paddr Physical address of the page (MUST be page-aligned) + * + * @return error if page is invalid + */ +sos_ret_t sos_physmem_set_kmem_range(sos_paddr_t ppage_paddr, + struct sos_kmem_range *range); + +#endif /* _SOS_PHYSMEM_H_ */ diff --git a/sos-code-article6/sos/types.h b/sos-code-article6/sos/types.h new file mode 100644 index 0000000..bf04314 --- /dev/null +++ b/sos-code-article6/sos/types.h @@ -0,0 +1,52 @@ +/* Copyright (C) 2004 The SOS Team + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#ifndef _SOS_TYPES_H_ +#define _SOS_TYPES_H_ + +/** + * @file types.h + * + * SOS basic types definition + */ + +/** Physical address */ +typedef unsigned int sos_paddr_t; + +/** Kernel virtual address */ +typedef unsigned int sos_vaddr_t; + +/** Memory size of an object (positive) */ +typedef unsigned int sos_size_t; +/** Generic count of objects */ +typedef unsigned int sos_count_t; + +/** Low-level sizes */ +typedef unsigned long int sos_ui32_t; /* 32b unsigned */ +typedef unsigned short int sos_ui16_t; /* 16b unsigned */ +typedef unsigned char sos_ui8_t; /* 8b unsigned */ +typedef signed long int sos_si32_t; /* 32b signed */ +typedef signed short int sos_si16_t; /* 16b signed */ +typedef signed char sos_si8_t; /* 8b signed */ + +typedef enum { FALSE=0, TRUE } sos_bool_t; + +/** Not a proper type, but highly useful with basic type + manipulations */ +#define NULL ((void*)0) + +#endif /* _SOS_TYPES_H_ */ |